The tests we did at the last seminar are, as a rule, not done manually. For testing purposes, a special program is written - a test driver, which conducts testing. Moreover, such programs are often written in a different language than the program being tested, or are created automatically using special utilities.

In this workshop, we will write a simple test driver ourselves in C# to test the Calculator functions, using the specification of the second workshop.

Comment. The program code has been slightly modified to simplify the compilation of individual modules. Thus, working with the variable is excluded

Program.res, and the CalcClass class is declared public.

First, let's look at the division function. We have already drawn up test requirements for it. For simplicity, we will use only four general test requirements.

• 1. Both input parameters belong to valid area, and the output value belongs to the valid region.
• 2. The first input parameter belongs to the valid region, the second does not belong to the valid region
• 3. The first input parameter does not belong to the valid region, the second one belongs to the valid region
• 4. Both input parameters belong to the valid region, but the function value does not belong to the valid region.

Let's create a program:

private void buttonStartDel_Click(object sender, EventArgs e)

richTextBoxl.Text = richTextBoxl.Text += "Test Case l";

richTextBoxl.Text += "Input data: a= 78508, b = -304 "; richTextBoxl.Text += "Expected result: res = 78204 && error = """+" ";

int res = CalcClass.Add(78508, -304); string error = CalcClass.lastError; richTextBoxl.Text += "Error code:" + error + " "; richTextBoxl.Text += "The resulting result is: " +"res = "+ res.ToString() +" error = "Terror. ToString() +" "; if (res == 78204 && error == "")

Sinitsyn S.V., Nalyutin N.Yu. Verification software

catch (Exception ex)

richTextBoxl.Text += "Test Case 2";

richTextBoxl.Text += "Input data: a= -2850800078, b = 3000000000 ";

int res = CalcClass.Add(-2850800078, 3000000000); string error = CalcClass.lastError; richTextBoxl.Text += "Error code:" + error + " "; richTextBoxl.Text += "The resulting result is: " + "res = " + res.ToString() + " error = " + error.ToString() + " "; if (res == 0 && error == "Error 06")

richTextBoxl.Text += "Test passed";

richTextBoxl.Text += "Test failed";

catch (Exception ex)

richTextBoxl.Text += "Exception caught: " + ex.ToString() + "pTest failed";

richTextBoxl.Text += "Test Case 3";

richTextBoxl.Text += "Input data: a= 3000000000, b = - 2850800078 ";

richTextBoxl.Text += "Expected result: res = 0 && error = "Error 06" ";

int res = CalcClass.Add(3000000000, -2850800078); string error = CalcClass.lastError; richTextBoxl.Text += "Error code: " + error+" "; richTextBoxl.Text += "The resulting result is: " + "res = " + res.ToStringO + " error = " + error.ToString() + " "; if (res == 0 && error == "Error 06")

richTextBoxl.Text += "Test passed";

richTextBoxl.Text += "Test failed";

catch (Exception ex)

richTextBoxl.Text += "Exception caught: " + ex.ToString() + "pTest failed";

richTextBoxl.Text += "Test Case 4";

richTextBoxl.Text += "Input data: a= 2000000000, b = 2000000000 ";

richTextBoxl.Text += "Expected result: res = 0 && error = YError 06" ";

int res = CalcClass.Add(2000000000, 2000000000); string error = CalcClass.lastError; richTextBoxl.Text += "Error code: " + error +" "; richTextBoxl.Text += "The resulting result is: " + "res = " +

Sinitsyn S.V., Nalyutin N.Yu. Software verification

res.ToString() + " error = " + error.ToString() + " "; if (res == 0 && error == "Error 06")

richTextBoxl.Text += "Test passed";

richTextBoxl.Text += "Test failed";

catch (Exception ex)

richTextBoxl.Text += "Exception caught: " + ex.ToString() + "pTest failed";

Listing 7.1. Program text

Each test case is inside a try-catch block in order to catch any exception thrown inside the Add() methods.

In this case, the file CalcClass.dll, in which all mathematical methods are implemented, must be added to the References of the project.

Let's test and get the following result:

Input data: a= 78508, b = -304 Expected result: res = 78204 && error = ""

Error code:

The resulting result: res = 78204 error =

Test passed

Input data: a= -2850800078, b = 3000000000 Expected result: res = 0 && error = "Error 06"

Error code: Error 06

The resulting result: res = 0 error = Error 06

Sinitsyn S.V., Nalyutin N.Yu.

Test passed Test Case 3

Input data: a= 3000000000, b = -2850800078 Expected result: res = 0 && error = "Error 06"

Error code: Error 06

Input data: a= 2000000000, b = 2000000000 Expected result: res = 0 && error = "Error 06"

Error code: Error 06

The resulting result: res = 0 error = Error 06 Test passed

We would have gotten exactly the same result during manual testing if the identified errors had been corrected. Note that with this approach to testing we are able to localize errors. If something does not work as it should, then we can confidently say that the error is contained in the division function, while at the last seminar we could not say where exactly it occurred.

Comment. We believe that the test driver itself is free of errors. Testing the test driver is beyond the scope of the topic being studied.

Handout

7.4.1. Program

You will be given .dll files that need to be tested using the "black box" method, and an example of a test driver.

Homework

Create a test plan and conduct unit testing of the following methods:

1. Finding the remainder.

/// Modulo division ///

/// divisible>

/// dividerragat>

/// ocTaTOK public static int Mod(long a, long b)

2. Unary plus.

Sh unary plus ///

III

III public static int ABS(long a)

3. Unary minus.

Sh unary minus ///

III

III public static int IABS(long a)

4. Subtraction.

Sh subtraction III

III washable ragash> Sh deductible> III pa3HOCTb public static int Sub(long a, long b)

Sinitsyn S.V., Nalyutin N.Yu.

5. Multiplication.

/// multiplication ///

/// multiplier> /// multiplier> /// npoH3BefleHHe public static int Mult(long a, long b)

6. Division.

Sh private III

III divisible>

Sh dividerragat>

III 4acTHoe public static int Div(long a, long b)

The calculator should be checked for accuracy when purchasing. Failure of metering devices is not dangerous, but, of course, this affects the wallets of their owners. This is expressed not only in overpayment for electricity or the amount of water consumed. Detection by the relevant services of an incorrect connection of the electric meter to the network (for example, it was turned in the other direction) will lead to the payment of a fine. But you can avoid all this if you know how to check.

Two ways to check if the calculator is working correctly

Having appeared back in the 70s, portable calculators received universal recognition. Since with their arrival, making various calculations has become much easier. Today, there are several types of calculators designed for a specific field of activity.

Types of calculators:

• Accounting – a number series in which is increased, they are able to automatically calculate profits, take into account taxes and convert currencies;
• Engineering - have the ability to calculate elementary functions in numbers and symbols;
• Graphic – capable of displaying pictures and graphs.

To perform various calculations on a calculator, it is enough to know how to enter the conditions for calculations and how to correctly obtain the result. But, as you know, it is not only human who makes mistakes; malfunctions occur even in the most reliable mechanisms and circuits. And the final result depends on the correctness of the calculation. And to prevent incorrect situations, use these verification methods for all types of calculators.

Since this check does not take much time, perform it at the stage of purchasing the calculator.

To check the functionality of the calculator, you need to square the number - 111111111 (9 units). If the resulting number corresponds to - 12345678987654321, then the calculator is working.

Second way. You need the number 12345679, multiply by 9. The result should be 111111111 (9 units).

Checking the electricity meter for serviceability

In order to check the electric meter for correct readings, you do not need to call an electrician. You can easily handle this yourself. And timely detection of a malfunction will protect yourself from overpaying for electricity.

Factors indicating that the electric meter is faulty:

• All appliances and household appliances are operating as usual, but electricity consumption has increased significantly;
• The operating time of household appliances and appliances has decreased, but electricity consumption has not decreased.

If, in your opinion, the meter is over-reading, the first thing to do is check it for correct connection. For single-phase meters, the connection is as follows: the first two contact terminals are occupied by the phase wire (come, go), the second two contacts are occupied by the neutral wire.

If you have a three-phase electric meter installed, the connection should be as follows: the first six contact terminals are occupied by three phase wires, and the seventh and eighth wires are neutral.

If you detect any malfunction of the electric meter, do not try to stop it, but immediately contact the appropriate service to fix it.

If the meter is connected to the network according to the standard, but continues to show overestimated kwh (kilowatt per hour), you need to check it for self-propelling. It's just as easy to do at home. It is necessary to stop the supply of electricity to all appliances and household appliances. Turn off all the machines in the panel or unplug all electrical appliances, turn off the lights. After 15 minutes, perform a visual check of the meter. The disk should not spin, and the LED should blink no more than once every 10 minutes.

What you need and how to check water meters yourself

All metering devices, including water meters, are tested at the manufacturer. But if you have doubts that your water meter correctly calculates the amount of water used, check the quality of its work.

To check the meter you will need:

• Scales;
• Container for collecting water;
• Calculator.

First of all, you need to weigh the container (the required volume is more than 10 liters) and write down the resulting numbers. Next, the instrument readings are recorded on this moment. Then, fill the container with water (medium water pressure). Then the filled container is weighed and meter readings are taken. Based on the fact that the mass of one cubic meter of water is one ton, you need to compare the volume of water in the container with what the meter shows (in liter equivalent) and divide the cubic meter by a thousand.

The convenience of this method is that serviceability can be checked without removing the water meter.

It is important to understand that to obtain more accurate results, you need an instrumental check of the meter. To do this, a metrological service employee is called, who checks the water meter with precision inspectors.

Options for how to correctly calculate electricity using a meter

Independent calculation of consumed electricity will allow you to avoid unnecessary waste in some cases. Money, as well as compare the results obtained with the numbers indicated on the receipt.

The calculation depends on the type of meter:

• Apartment;
• Common house.

For a residential meter, you can calculate electricity as follows. On a certain day of the month, it is necessary to record readings from the meter. All numbers that are located with a comma or are marked in a different color are recorded. Then, on the same day of the next month, the meter readings are taken again and the figures of the previous month are subtracted from the figures of this month. This result will be the amount of electricity you consumed per month.

To calculate electricity using a common house meter, you need to subtract the readings of last month from the meter readings of this month. Then the resulting volume of consumed electricity must be divided by the area of ​​​​all living quarters in the house. The resulting figure will be equal to the amount of electricity consumed per m2. Next, we multiply this figure by the number of m2 you have, and we get the amount that you need to pay according to the common house meter for electricity.

Failure of metering devices does not pose any danger, but it undoubtedly affects the wallets of their owners. This is expressed not only in overpayment for electricity or the amount of water consumed. Detection by the relevant services of an incorrect connection of the electric meter to the network (for example, it was turned in the other direction) will lead to the payment of a fine. But you can avoid all this if you know how to check.

Two ways to check if the calculator is working correctly

Having appeared back in the 70s, portable calculators received universal recognition. Since with their arrival, making various calculations has become much easier. Today, there are several types of calculators designed for a specific field of activity.

Types of calculators:

• Accounting – a number series in which is increased, they are able to automatically calculate profits, take into account taxes and convert currencies;
• Engineering – have the ability to calculate elementary functions in numbers and symbols;
• Graphic – capable of displaying pictures and graphs.

To perform various calculations on a calculator, it is enough to know how to enter the conditions for calculations and how to correctly obtain the result. But, as you know, it is not only human who makes mistakes; malfunctions occur even in the most reliable mechanisms and circuits. And the final result depends on the correctness of the calculation. And to prevent incorrect situations, use these verification methods for all types of calculators.

Since this check does not take much time, perform it at the stage of purchasing the calculator.

To check the functionality of the calculator, you need to square the number - 111111111 (9 units). If the resulting number corresponds to - 12345678987654321, then the calculator is working.

Second way. You need the number 12345679, multiply by 9. The result should be 111111111 (9 units).

Checking the electricity meter for serviceability

In order to check the electric meter for correct readings, you do not need to call an electrician. You can easily handle this yourself. And timely detection of a malfunction will protect yourself from overpaying for electricity.

Factors indicating that the electric meter is faulty:

• All appliances and household appliances are operating as usual, but electricity consumption has increased significantly;
• The operating time of household appliances and appliances has decreased, but electricity consumption has not decreased.

If, in your opinion, the meter is over-reading, the first thing to do is check it for correct connection. For single-phase meters, the connection is as follows: the first two contact terminals are occupied by the phase wire (come, go), the second two contacts are occupied by the neutral wire.

If you have a three-phase electric meter installed, the connection should be as follows: the first six contact terminals are occupied by three phase wires, and the seventh and eighth wires are neutral.

If you detect any malfunction of the electric meter, do not try to stop it, but immediately contact the appropriate service to fix it.

If the meter is connected to the network according to the standard, but continues to show overestimated kwh (kilowatt per hour), you need to check it for self-propelling. It's just as easy to do at home. It is necessary to stop the supply of electricity to all appliances and household appliances. Turn off all the machines in the panel or unplug all electrical appliances, turn off the lights. After 15 minutes, perform a visual check of the meter. The disk should not spin, and the LED should blink no more than once every 10 minutes.

What you need and how to check water meters yourself

All metering devices, including water meters, are tested at the manufacturer. But if you have doubts that your water meter correctly calculates the amount of water used, check the quality of its work.

To check the meter you will need:

• Scales;
• Container for collecting water;
• Calculator.

First of all, you need to weigh the container (the required volume is more than 10 liters) and write down the resulting numbers. Next, the readings of the device at the moment are recorded. Then, fill the container with water (medium water pressure). Then the filled container is weighed and meter readings are taken. Based on the fact that the mass of one cubic meter of water is one ton, you need to compare the volume of water in the container with what the meter shows (in liter equivalent) and divide the cubic meter by a thousand.

The convenience of this method is that serviceability can be checked without removing the water meter.

It is important to understand that to obtain more accurate results, you need an instrumental check of the meter. To do this, a metrological service employee is called, who checks the water meter with precision inspectors.

Options for how to correctly calculate electricity using a meter

Independent calculation of the consumed electricity will allow you, in some cases, to avoid wasting money, as well as compare the results obtained with the figures indicated on the receipt.

The calculation depends on the type of meter:

• Apartment;
• Common house.

For a residential meter, you can calculate electricity as follows. On a certain day of the month, it is necessary to record readings from the meter. All numbers that are located with a comma or are marked in a different color are recorded. Then, on the same day of the next month, the meter readings are taken again and the figures of the previous month are subtracted from the figures of this month. This result will be the amount of electricity you consumed per month.

To calculate electricity using a common house meter, you need to subtract the readings of last month from the meter readings of this month. Then the resulting volume of consumed electricity must be divided by the area of ​​​​all living quarters in the house. The resulting figure will be equal to the amount of electricity consumed per m2. Next, we multiply this figure by the number of m2 you have, and we get the amount that you need to pay according to the common house meter for electricity.

How to prevent the electric meter from shaking (video)

Despite the fact that all equipment undergoes various tests in production, it may malfunction. There are several reasons for this, long duration of operation or improper installation with further use. But, knowing how to identify malfunctions, you can protect yourself from unforeseen situations.

Humans tend to make mistakes. He doesn’t like to admit it publicly, but he is well aware of it. That is why humanity has created many technical devices, the task of which is to simplify, speed up and guarantee the accuracy of various popular processes. But what if machines start making mistakes? In theory, this is impossible, because the electronic “mind” is not subject to emotions, distractions and fatigue. But in practice, no, no, and doubts creep in about the reliability of the data obtained. Therefore, taking into account that there are no miracles in electronics, but only bad contacts, let's try to play it safe and learn how to check at least a calculator for accuracy.

Features of the device and operation of the calculator
An electronic computing device, or more simply put, a calculator, is very familiar to most modern schoolchildren, starting from junior classes. Although their parents could only dream of such a convenient “cheat sheet” and that’s all arithmetic operations performed mentally or “in a column” on a sheet of paper. The life of schoolchildren and housewives keeping account of the family budget became easier at the very beginning of the 1970s, when relatively compact calculators (they could be held in one hand) went on sale.

Since then, specialized engineering (“scientific” ones, support the calculation of elementary functions, numeric and symbolic), accounting (with an increased number series and the ability to automatically calculate profits, take into account taxes, convert currencies), financial (can calculate the amounts of cash flows, discounts, payments) have appeared for loans in the banking sector) and even graphic (display pictures and graphs). The simplest arithmetic calculators have become very miniature and are built into mobile phones and wristwatches. But the typical design of a compact electronic calculator remains the same in essence.

Outward form factors different options The display and keyboard for data entry are displayed, and memory and processor chips of varying power are hidden inside. They encrypt numerical data that people understand and need in the form of machine binary coded decimal code and use it for arithmetic calculations. Typically these math problems are solved according to one of three paths of the logic of operations. These are standard algebraic logic, arithmetic logic and the so-called calculation logic with reverse Polish notation. But for most users it is enough to know in what sequence to enter the calculation conditions and how to get their result.

For example, to find out how much “30*5+45” will be, you will have to press the keyboard buttons in sequence: “3”, “0”, “×”, “5”, “+”, “4”, “5”, and then "=". According to the laws of arithmetic, after pressing the plus sign, the multiplication of 30 by 5 will be performed. At this moment, the display will display the intermediate result “150” for example, and only after pressing the button with the equal sign on the keyboard will the final result of the calculations be displayed: “195”. As for the reliability of this information, all that remains is to trust the electronic “brain” or check the serviceability of the calculator, thereby confirming or disproving the accuracy of its calculations.

Checking the calculator for accuracy
You can check the accuracy of the calculator at any time when you have such a desire or doubts about its serviceability. Because this will not require any additional devices from you and can be done exclusively by the unit being tested. Due to the demand and prevalence of calculators around the world, inventive users and manufacturing companies themselves have come up with several ways to verify the accuracy of electronic calculations:

1. When squaring the number 111111111, the value 12345678987654321 should be displayed on the calculator screen. Such a numerical “palindrome” indicates the serviceability of the computer equipment.
   
2. When you multiply the number 12345679 by 9, nine units appear on the display of an precision calculator: 111111111.
   
3. When sequentially introducing the conditions of the example 100*10/2+16*4, the result of the calculations should be equal to 564. If your calculator coped with it without errors, then everything is in order with its algebraic logic.
   

But there are situations when such relatively simple calculations are not enough. For example, when we're talking about about certain scientific or technical processes. In these cases, what is needed is not an approximate and rounded calculation, but a calculation as close as possible to the true one. And practice shows that simple household calculators can give an error of true meaning tens and even hundreds of times (in long sequences of fractional data). In this case, the conditions of the problem often stipulate the requirement of number accuracy up to n digits (in each individual case).

For this, there is a formula that is “too tough” for almost any of the currently existing calculators. But with its help you can find out exactly how wrong your technique is. Ask the calculator to calculate the result using this formula, but enter it not in parts, but as a whole array:

An answer equal to approximately minus one indicates that you can safely trust your calculator even with the most complex calculations that require high accuracy. But be prepared for the fact that even the most modern technical calculator will not perform well in such a test. In this case, we can advise you to use so-called emulators, or computer programs, simulating electronic technology, but differing from it in the large amount of memory, the complexity of computational processes and, accordingly, the accuracy of the results.

What else to look for when choosing a calculator
It is best to check the calculator for accuracy at the very beginning of its use, immediately before making a purchase, in order to immediately protect your work from possible errors. At the same time, pay attention to other characteristics of the device that affect the accuracy of calculations; even if it is smaller than the processor, it is still noticeable. The size, resolution and contrast of the display must correspond to the complexity of the tasks and accommodate a sufficient number of symbols, as well as display them clearly. The image on the keys, the quality of its application, resistance to abrasion, as well as the size and location of the buttons should be convenient, practical and intuitive. Otherwise, you run the risk of getting confused over and over again when entering data and starting this sometimes painstaking process all over again.

High-quality equipment must be supplied with branded packaging and must be accompanied by instructions for using the device. By the way, in these instructions, conscientious manufacturers always indicate a method for checking the accuracy of the calculator, one of the arithmetic ones that we discussed above. And, of course, check the availability and compliance with warranty conditions from both the manufacturer and the seller of the calculator. Because if a malfunction is detected and regular calculation errors occur, you should be able to return the failed device back. We wish you the right choice and accurate calculations.

How to check your calculator for accuracy

Today, calculators are built into literally everything: watches, phones, smartphones, players and other electronic devices. However, the calculator, as an independent device, will be in demand for a very long time.

It is necessary for schoolchildren and students, housewives and accountants, engineers and managers.

It’s not difficult to buy a calculator that’s right for you; you just need to know exactly which calculator you need.

Exist different types similar devices:

Regular (simplest) with a minimum set of functions. Suitable for schoolchildren and those who usually perform simple calculations.

Accounting - as a rule, desktop with large buttons. Has special “money” buttons, automatic rounding, etc.

Banking (financial) – intended for calculating interest and other specific operations.

Engineering and programmable calculators have many functions and allow you to perform complex calculations. Can be programmed by the user.

Of course, the calculator must have a durable case, a capacious battery, and a sufficient number of digits on the display. But the main thing in the operation of any computing device is accuracy and reliability.

There are several simple ways to find out if the device is lying. First of all: try to multiply or add as much as possible big numbers.

If the calculator does not display an error message or break, great, the very first test has been passed.

Give some simple addition examples, like: 3+6=9. Then it’s more complicated: 1111x1111=1234321.

Why exactly this example? And it’s easy to remember! Or again: 11111x11111=123454321. There is an example for subtraction: 12345678-123456789=-111111111.

There are other verification formulas that are no different from any others, except that they are easy to remember:

• 12345679x9=111111111
• 123123123: 1001001=123
• 12345679x8=98765432

And here’s another interesting way - 12345679 * 7.2 will turn out to be 88888888888, that is, all eights, you can immediately see that the logic is not broken and the display is all working!

Testing the calculator will not take much time. However, if a calculator is needed to carry out engineering calculations, apply functions, etc., then they need to be checked.

1bon.ru

electric meter and readings, electricity at home

The calculator should be checked for accuracy when purchasing. Failure of metering devices is not dangerous, but, of course, this affects the wallets of their owners. This is expressed not only in overpayment for electricity or the amount of water consumed. Detection by the relevant services of an incorrect connection of the electric meter to the network (for example, it was turned in the other direction) will lead to the payment of a fine. But you can avoid all this if you know how to check.

Two ways to check if the calculator is working correctly

Having appeared back in the 70s, portable calculators received universal recognition. Since with their arrival, making various calculations has become much easier. Today, there are several types of calculators designed for a specific field of activity.

Types of calculators:

• Accounting – a number series in which is increased, they are able to automatically calculate profits, take into account taxes and convert currencies;
• Engineering – have the ability to calculate elementary functions in numbers and symbols;
• Graphic – capable of displaying pictures and graphs.

To perform various calculations on a calculator, it is enough to know how to enter the conditions for calculations and how to correctly obtain the result. But, as you know, it is not only human who makes mistakes; malfunctions occur even in the most reliable mechanisms and circuits. And the final result depends on the correctness of the calculation. And to prevent incorrect situations, use these verification methods for all types of calculators.

Since this check does not take much time, perform it at the stage of purchasing the calculator.

To check the functionality of the calculator, you need to square the number - 111111111 (9 units). If the resulting number corresponds to - 12345678987654321, then the calculator is working.

Second way. You need the number 12345679, multiply by 9. The result should be 111111111 (9 units).

Checking the electricity meter for serviceability

In order to check the electric meter for correct readings, you do not need to call an electrician. You can easily handle this yourself. And timely detection of a malfunction will protect yourself from overpaying for electricity.

Factors indicating that the electric meter is faulty:

• All appliances and household appliances are operating as usual, but electricity consumption has increased significantly;
• The operating time of household appliances and appliances has decreased, but electricity consumption has not decreased.

If, in your opinion, the meter is over-reading, the first thing to do is check it for correct connection. For single-phase meters, the connection is as follows: the first two contact terminals are occupied by the phase wire (come, go), the second two contacts are occupied by the neutral wire.

If you have a three-phase electric meter installed, the connection should be as follows: the first six contact terminals are occupied by three phase wires, and the seventh and eighth wires are neutral.

If you detect any malfunction of the electric meter, do not try to stop it, but immediately contact the appropriate service to fix it.

If the meter is connected to the network according to the standard, but continues to show overestimated kwh (kilowatt per hour), you need to check it for self-propelling. It's just as easy to do at home. It is necessary to stop the supply of electricity to all appliances and household appliances. Turn off all the machines in the panel or unplug all electrical appliances, turn off the lights. After 15 minutes, perform a visual check of the meter. The disk should not spin, and the LED should blink no more than once every 10 minutes.

What you need and how to check water meters yourself

All metering devices, including water meters, are tested at the manufacturer. But if you have doubts that your water meter correctly calculates the amount of water used, check the quality of its work.

To check the meter you will need:

• Scales;
• Container for collecting water;
• Calculator.

First of all, you need to weigh the container (the required volume is more than 10 liters) and write down the resulting numbers. Next, the readings of the device at the moment are recorded. Then, fill the container with water (medium water pressure). Then the filled container is weighed and meter readings are taken. Based on the fact that the mass of one cubic meter of water is one ton, you need to compare the volume of water in the container with what the meter shows (in liter equivalent) and divide the cubic meter by a thousand.

The convenience of this method is that serviceability can be checked without removing the water meter.

It is important to understand that to obtain more accurate results, you need an instrumental check of the meter. To do this, a metrological service employee is called, who checks the water meter with precision inspectors.

Options for how to correctly calculate electricity using a meter

Independent calculation of the consumed electricity will allow you, in some cases, to avoid wasting money, as well as compare the results obtained with the figures indicated on the receipt.

The calculation depends on the type of meter:

• Apartment;
• Common house.

For a residential meter, you can calculate electricity as follows. On a certain day of the month, it is necessary to record readings from the meter. All numbers that are located with a comma or are marked in a different color are recorded. Then, on the same day of the next month, the meter readings are taken again and the figures of the previous month are subtracted from the figures of this month. This result will be the amount of electricity you consumed per month.

To calculate electricity using a common house meter, you need to subtract the readings of last month from the meter readings of this month. Then the resulting volume of consumed electricity must be divided by the area of ​​​​all living quarters in the house. The resulting figure will be equal to the amount of electricity consumed per m2. Next, we multiply this figure by the number of m2 you have, and we get the amount that you need to pay according to the common house meter for electricity.

How to prevent the electric meter from shaking (video)

Despite the fact that all equipment undergoes various tests in production, it may malfunction. There are several reasons for this, long duration of operation or improper installation with further use. But, knowing how to identify faults, you can protect yourself from unforeseen situations.

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How to check the calculator? Does he think correctly?

How to check the calculator? Does he think correctly?

Good question. Because, on the one hand, it can be checked by performing several simple operations with it, but on the other hand, the correct answer to them is still not a guarantee that the calculator will not make mistakes in some calculations with in large numbers. If you take calculators for sale, then you need to take them from trusted companies, such as Casio, Toshiba (and once upon a time Elektronika) since there, I think, they have checked everything well, tested it, and use the same software templates , time-tested. But some downloadable or online calculator may make a mistake somewhere, and this may not even be the fault of the developer, but because the development environment in which he did it compiles calculations with errors or even errors if he used and the development tool is not professional, but some kind of amateur one.

In any case, you can only check it in practice. Make several calculations, several for each function:

One calculation with integer, positive numbers.

The second with integers, including negative ones.

Third - with decimals, also using both positive and negative numbers.

Check what division by zero produces.

Also check for overflow.

Also check how buttons such as M+, M-, etc. work.

Run simple math examples that you can do in your head or on paper. If you and the calculator get the same answer, then your calculator is fine.

The easiest way, of course, is to ask such a problem to a calculator, the answer to which you know. The most reliable way would be a problem that contains all the numbers, for example 123456789 * 9 equals 111111111 (you can also divide 111111111 by 9 to get the number 123456789). You can replace these options with any others - the main thing is to know the solution in advance.

You can check whether the calculator calculates correctly by performing basic calculations on it. It is important to check all the buttons on the calculator. Only then can one judge whether it is working or not.

Does the calculator calculate correctly...

To check the functioning of any calculator, you need to perform a certain calculation operation on nm with a known answer, but one in which all the numerical digits of the calculator would be involved. For example:

12345679 x 9 = 111111111

Accordingly, performing the reverse operation, dividing 111111111 by 9 should result in 12345679.

The calculator that showed this calculation result is working properly.

To test the calculator, you need to perform a few simple steps on it. You can use a second calculator to make sure the first one is correct. The important thing is that you need to check each button, that is, make calculations using every single button.

This is quite easy to do. This is not done at the programming level. To test the calculator, you need to ask problems to which you know the answer. The main thing is that during checks all keys are used to make sure that it works correctly.

info-4all.ru

How to check the accrual of VAT 🚩 how to read the balance sheet for account 76 🚩 Taxes

Instructions

First, check that the sales book is formatted correctly. Each invoice must have serial number, date, product name, VAT amount and total cost. Under no circumstances is sequential numbering permitted.

Review the presence of all required signatures and seals. If there are corrections, they must be approved by the head or chief accountant of the enterprise. Be sure to carry out a reconciliation report with customers before stapling the sales book.

In the invoice journal, you must verify the following data: invoice number and date, VAT amount, total cost, name of the buyer, TIN number. Be sure to check the final amounts. To do this, use the balance sheet. If the products were donated, the invoice does not need to be recorded in this journal. If partial payment is made, the invoice issued for the advance amount will not be recorded.

After checking, number the sales book, sew it together, and seal the information with the blue stamp of the organization’s seal and the signature of the manager. On the last page on the reverse side, write how many pages there are in the book.

Proceed to check your purchase ledger. To do this, carry out reconciliation reports with suppliers. Check not only the amounts, but also the numbers and dates of invoices. Be sure to check that the organization details are correct.

After this, check the amounts with the data indicated in the balance sheet. Remember that tax documents are registered in the period when the right to deduct VAT arises.

If you notice an error in an invoice for the last tax period, cancel it. Fill out an additional sheet, draw up an updated VAT return and submit it to the Federal Tax Service. If an invoice is missed, you should do the same.

www.kakprosto.ru

Online calculator

Finding reciprocal number	Enter the number for which you want to find the inverse, press the 1/x button
Extracting square root (2nd root)	Enter the number you want to extract from Square root, press the √x button
Extracting cube root (3rd root)	Enter the number from which you want to extract the cube root, press the 3√x button
Extracting the root of a given degree	Enter the number from which you want to extract the root of a given degree, press the y√x button, enter the value of the degree of the root to be extracted
Calculation decimal logarithm(logarithm to base 10)	Press the log button, enter the number for which you want to calculate the logarithm in base 10
Operations with number e	If you need to perform a mathematical operation with the number e or using this constant, then instead of entering the value of this number you just need to press the e button
Raising the number 10 to the power	Press the 10x button, enter the value of the power to which you want to raise the number 10
Squaring (2nd degree)	Enter the number to be squared, press the x2 button
Cube (3rd degree)	Enter the number to be cubed and press the x3 button
Raising to a given power	Enter the number that needs to be raised to a given power, press the xy button, enter the value of the power
Operations with interest	To calculate what a certain number of percent of a number is, you need to enter this number, press the x button (i.e., multiply), enter the number of percent and press %. To add to (or subtract) a certain number of percent from it, you need to enter this number, press the + button (or –, respectively), then enter the number of percents and press %
Operations with imaginary unit (number i)	To use the imaginary unit (number i) in calculations, you must press the i button

www.calculator-pro.ru

methods, calculations, formulas and examples

Small errors in the calculation of VAT on the part of an organization may be perceived by the tax inspectorate as an attempt to deceive the state. A trivial, even minor, error in accrual can result in penalties and fines for the enterprise. Serious underpayments may result in legal proceedings.

That is why accounting staff try to especially carefully monitor the accuracy of accruals. To check they use various ways. And today we will tell you how to check VAT online and without using the Internet, who checks statistics on import VAT in the Russian Federation, how to check the registration of a payer in the database and other important nuances.

How to check VAT yourself

You can conditionally check the calculation of VAT in two ways: independently and during a tax audit. Regulatory authorities have their own methods. Internal accounting uses several methods.

You need to independently check the correctness of the calculation of value added tax in the following ways:

• For advance payments
• Sales check
• Analysis of calculations from purchase books.

Timely monitoring of the correctness of calculations allows you to avoid many problems. This is the right approach, but it does not promise to be simple and fast.

This video will tell you how to check a VAT payer:

By total turnover of product sales

With this method of verification, it is easy to identify errors in VAT calculations. The process itself is not complicated, but it requires a lot of time, care and perseverance. It is required to analyze all records of the following operations:

• documentation of advance payments
• return of registered goods
• information on the fulfillment of their obligations by tax agents
• documents confirming receipt of any funds increasing the tax base
• data on receipt of funds during sales, provision of services or performing work in including for your own needs, when transferring property rights.

Transactions that are not subject to tax deductions are not taken into account. All other data must be carefully calculated. Analysis of sales ledger data should always be performed in conjunction with purchase documentation.

According to the purchase book

When calculating VAT using a purchase ledger, you can determine the amount of funds to be deducted. For VAT payers, this document is required, and when checking independently, the accountant needs to take into account the following items:

• Advance documentation
• Travel expenses
• Invoices from sellers
• Adjustment invoices
• Expenses for construction and installation works for own needs
• Customs declaration and related documents
• Application for import of goods and payment of indirect taxes.

The data obtained is required for the correct calculation of VAT. They allow you to determine the amount of deductions that reduce the amount of tax, but must be documented.

According to the balance sheet

It is necessary to calculate the volume of VAT amounts to be paid to the budget and determine the amount of funds to be reimbursed (for example, for construction, in case of overpayment from the budget, etc.). It is also necessary to take into account the paid amounts from advances received and sent to counterparties.

For correct calculation, you need to compare the debit data on subaccounts 60.2 and 62.1, take into account credit calculations (60.1 and 62.2). Determine the balance of the listed accounts at the end of the tax period, check with the books of purchases and sales. Additionally, you need to check the VAT on advances and purchased valuables. If calculated correctly, the data on the debit and credit subaccounts will coincide with sales and purchases. Otherwise, you need to check the correctness of the information entered in sales, purchases and advance payments.

Let's find out how to check VAT on advances received.

For advance payments

Advance payments subject to VAT require special attention. Accounting departments often have questions regarding calculations. This happens especially often if the advance payment and shipment of the goods occurred in the same tax period.

A number of orders of the Ministry of Finance imply separate calculations for the advance payment and the remaining amount to be paid. In some cases, it is acceptable not to issue an invoice for the advance payment. This occurs in the case of advance payment and shipment of goods on the same day. It is also sometimes practiced to refuse to calculate VAT on an advance payment if the difference with shipment is no more than 5 days.

The Federal Tax Service of Russia recommends avoiding this practice in order to eliminate unnecessary questions during the inspection. The tax base does not increase from the timely calculation of VAT, so its correct documentation prevents controversial situations with regulatory authorities. In this case, it is necessary to take into account not only advances paid, but also received.

We will tell you below how tax authorities (tax authorities) check the VAT return.

This video will tell you how to get a VAT deduction and then check its accrual:

Check through the tax office

When drawing up VAT documentation, you need to be extremely careful; they are carefully studied by the tax authorities. Declarations will also be verified during a desk audit. First of all, specialists check the submitted declarations and determine how correctly the tax base is formed, paying special attention to deductions for shipments.

The following nuances must be taken into account:

• Sale and purchase of debts
• Agreements for the assignment of financial rights
• Free transfer of property
• sale of property subject to VAT
• Receiving profit under contracts with counterparties
• Price of products not subject to taxation.

These data are compared with the information from the submitted declaration. The correspondence of the numbers, dates and other data of the organization’s invoices with their entries in the relevant documents must be examined. All advance payments and the final correctness of filling out the declaration are also subject to analysis.

All enterprises paying VAT need to know that the powers of tax inspectors have expanded. Now, according to Law No. 134-FZ, they can conduct an in-depth audit when providing documents for tax reimbursement from the budget. To prevent unpleasant consequences It is necessary to conduct a thorough independent check of the correctness of VAT calculations before submitting documentation to the tax office.

The video below will tell you how to check VAT and how to apply tax codes:

uriston.com

Simple online calculator. A very simple and convenient calculator that you can use for free directly in your browser

On this page you can use a simple calculator online and absolutely free. A simple calculator performs addition, subtraction, multiplication and division of numbers. The only thing simpler than this calculator is a wooden abacus.

How to use a simple calculator?

You can use a simple calculator using your mouse or your keyboard, whichever is more convenient for you. It works online right in your browser. Using a calculator, you can decide the most simple tasks, not requiring complex calculations. To get started, press any number key. After that, you will see it on the calculator display, as well as a little lower, on the calculation panel. Now click on one of the mathematical actions whose buttons are to the right of the numbers. Then enter one of the numbers again and click on the = (equals) button. The result of a simple calculator's calculations will be displayed on the screen, and just below you will see the entire mathematical example entirely.

Controlling the calculator using the keyboard:

Numbers 0-9 - any numbers on the keyboard. Actions +-*/ - similar keys on the right side of the keyboard. Delete a character - Backspace key. Delete all - Del (or Delete) key.

Advantages of a simple online calculator?

The main advantages of this calculator are its simplicity and accessibility. If you need to carry out simple calculations, then you just need to go to this page and calculate everything without any problems. Calculations can be made on any calculator and even in your head, but here you don’t need to make unnecessary movements: just open the page and work with the calculator absolutely free.

The calculator interface is really very simple. It contains all the basic arithmetic operations: addition, subtraction, multiplication and division. This is the gold standard, allowing you to perform most household calculations, the need for which arises very often. Thanks to this minimalism, nothing will distract you from the main task. That is why the simplest calculator is the most effective way count simple examples.

Additional features of a simple calculator

While working with the virtual calculator, you can change its size. In the upper left corner online applications it can be changed using the plus and minus buttons. There are three sizes available: small (letter "M"), medium (letter "C") and large (letter "B"). Installed by default the average size. Also, the mathematical example, which is automatically written under the main display of the calculator, can be copied using the right mouse button. To do this, you need to select it and click “Copy” in the corresponding menu. To use a simple calculator regularly, you will find it convenient to add it to your browser bookmarks or bookmarks social network using special buttons on the left side of the screen.