Math Tests - mathematics practice questions - Adding and subtracting 1-10000 in columns

Math Tests - mathematics practice questions

Adding numbers 1-100 in columns (no carrying)

Adding numbers in columns

When adding larger numbers, it is often not enough to calculate mentally and it is better to use the vertical method of addition (or in columns). The example below shows the numbers 14 and 32. We write these numbers on top of each other so that the ones are under the ones, the tens are under the tens, etc. We start the calculation from the right hand side. Let's add the numbers to the ones position and then to the tens.

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It also happens very often that the sum of two digits exceeds ten. Let's take the example of 75+67. Here we have to add 5 and 7, which together is 12. In this case, we write only the last digit of the sum in the ones position, i.e. 2. We have to carry the digit one to the tens column, so we add this digit (one) to 7 and 6. The result is 14. Since there are no more digits to add in the hundreds position, we write the number 14 at the beginning of the result.

453

Adding numbers 1-100 in columns (with carrying)

Adding numbers in columns

When adding larger numbers, it is often not enough to calculate mentally and it is better to use the vertical method of addition (or in columns). The example below shows the numbers 14 and 32. We write these numbers on top of each other so that the ones are under the ones, the tens are under the tens, etc. We start the calculation from the right hand side. Let's add the numbers to the ones position and then to the tens.

451

It also happens very often that the sum of two digits exceeds ten. Let's take the example of 75+67. Here we have to add 5 and 7, which together is 12. In this case, we write only the last digit of the sum in the ones position, i.e. 2. We have to carry the digit one to the tens column, so we add this digit (one) to 7 and 6. The result is 14. Since there are no more digits to add in the hundreds position, we write the number 14 at the beginning of the result.

453

Subtracting 1-100 numbers in columns (no carrying)

Subtracting numbers in columns

If we are subtracting larger numbers, it is easier for us to use subtraction below one another (or in columns). Let's look at the example below (74−31). We write the numbers below each other so that the minuend (the number from which we are subtracting) is above and the subtrahend (the number which we are subtracting) is below it. The numbers must be aligned to the right below each other, so the ones are under the ones, the tens under the tens, etc. We start the calculation from the right hand side. We subtract the numbers to the ones place and then to the tens place.

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It often happens that when subtracting two digits, the upper number is smaller than the lower one. Consider the example 74−39 (see below). Here we need to subtract 9 from 4 (4−9). In this case, we borrow a ten (we add the number 1 before the number 4) and count 14−9, which is 5. Next, we count 7−3. However, we must not forget the ten that we borrowed. We transfer it as the number 1, so we count 7−(3+1). The result is 3. There are no more digits to be subtracted in the hundreds position, so the total result is 35.

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