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 basic mathematics image

Subtracting whole numbers



Subtracting whole numbers is the inverse operation of adding whole numbers.

Instead of adding two numbers to get a sum, you are removing one number from another to get a difference First, look at the following simple simple subtraction problems

subtraction-image

The first is 8 − 4 = 4. Thinking about money, you have 8 dollars and you spend 4, you are left with 4

Subtractions with one digit are usually fairly easy.

Things start getting complicated when you have more than one digit and you cannot remove the number at the bottom from the number on top such as when doing 85 − 8

Study the following example carefully because the concept of borrowing a ten is illustrated here

subtraction-image


Since you could not remove 8 from 5, you borrowed a ten from 8 tens and add that to 5 to make it 15

You can also write the problem without the tens and the ones to make it look simpler as illustrated below

subtraction-image


Another example

Once again, study the following example carefully. If you understand it and the one before, you should be well on your way to mastering subtracting

subtraction-image


Step #1

Borrow a 10 from 2 tens

The problem becomes

subtraction-image


Step #2

Borrow 1 hundred from 4 hundreds. 1 hundred = 10 tens. Then add 10 tens to 1 ten to make it 11 tens

subtraction-image


Step #3

Borrow 1 thousand from 5 thousands. 1 thousand = 10 hundreds. Then add 10 hundreds to 3 hundreds to make it 13 hundreds

Then, just subtract now since all numbers at the bottom are smaller than the number on top

subtraction-image







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