Apply the Commutative Property of Addition

Today we'll learn a special trick for adding. Let's start with two plus seven.

Here is our problem: two plus seven.

Let's use a number line to find the answer.

Start at zero. Jump two. We land on two.

Now jump seven more. One, two, three, four, five, six, seven.

We landed on nine. So two plus seven equals nine.

Now watch this — what if we swap the numbers around?

Seven plus two. The same numbers, just in a new order.

Start at zero. This time, jump seven first.

Then jump two more.

We land on nine again!

Swapping the order doesn't change the sum. That's the commutative property of addition.

So when adding, we can start with the bigger number to make it easier!