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
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
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
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
Step #1
Borrow a 10 from 2 tens
The problem becomes
Step #2
Borrow 1 hundred from 4 hundreds. 1 hundred = 10 tens. Then add 10 tens to 1 ten to make it 11 tens
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