Math Basics: Subtraction

Uploaded by gcflearnfree on 04.03.2011

Subtraction is used to find the difference between two numbers.
You can also think it as the opposite of addition.
Instead of putting two or more numbers together like you do when you add,
when you subtract, you're taking a number apart.
Suppose you have five apples. And you use three of them to make a pie.
That means you have two apples left.
You can write this as five minus three equals two.
The minus sign is use when you subtract.
An easy way to subtract numbers is to stack them
If you want to subtract six from eighteen,
first stack eighteen, the larger of the two numbers, on top of six.
Notice that the ones positions for each of the two numbers are lined up vertically.
Put a minus sign on the left of the stack and draw a line at the bottom.
Now you're ready to subtract.
First, subtrack six from eight in the ones place. Eight minus six is two, so
put a two below the line.
There is nothing below the one in the tens place to take away, so bring the one below the line
The answer, or difference, is twelve.
Let's try another problem.
Twenty four minus five
Since four is smaller than five,you're going to have to borrow from the number
to it's left, two.
Two is in the tens place, which means that we have two tens.
Borrow one of them and add it to the four in the ones place to get fourteen.
Cross out the two and replace it with a one, since we only have one ten left
after borrowing.
Fourteen minus five equals nine, so put a nine below the line.
Since there's nothing to subtract from the one remaining in the tens place, bring
the one down below the line.
The answer, or difference, is nineteen.
Now you know the basics of subtraction.