Help students learn six underlying concepts of addition and subtraction through real-world examples and fun activities

Estimating Sums and Differences of Whole Numbers

It may seem too good to be true, but you can use estimation to make adding and subtracting easy.

Properties of Addition

The best way to win the game is to play by the rules. Learn these three rules for addition, and you will be an adding champion.

Relating Addition and Subtraction

Did you know that you can undo addition by using subtraction? And you can undo subtraction with addition, too. This neat little trick is called inverse operations.

Addition and Subtraction Without Regrouping

Addition and subtraction are everywhere. Sometimes you just have to know how much, and this is how to do it.

Addition With Regrouping

Finding the sum, or total, of two or more numbers can be a snap. The secret is simple: learn how to line up the problem.

Subtraction With Regrouping

When your subtraction problem calls for regrouping, have no fear! With these easy steps, you will be a subtracting sensation.