Adding It Up

Lesson Plan - Get It!

Audio:

Dive into adding and subtracting rational numbers using a concept called zero pairs.

Zero pairs happen when you combine a positive number and a negative number that have the same absolute value. These opposites cancel each other out, giving you zero.

Here’s how it works.

Iimagine you have counters to represent numbers. Yellow counters are positive, and red counters are negative. If you place a yellow and red counter together, they cancel each other out because a positive and a negative of the same value make zero.

Practice this with an example.

Start with 4 yellow counters (+4) and 6 red counters (-6).

• How many counters are there in total?

There are 10 counters in total (4 yellow + 6 red). But now you need to figure out the value. To do this, you have to get rid of the zero pairs.

• How many zero pairs can you eliminate?

Since each yellow counter (+1) can cancel out each red counter (-1), you can eliminate 4 zero pairs.

• After eliminating the zero pairs, how many counters are left?

You will have 2 red counters left. So, the total value is -2.

Your number sentence for this would be: +4 + (-6) = -2 or -6 + 4 = -2.

Keep practicing by creating your own zero pairs on the Adding It Up: Get It worksheet located in Downloadable Resources in the right-hand sidebar.

Place the following counters on your mat, find the value, and write a number sentence to represent the problem.

7 red and 4 yellow

5 yellow and 2 yellow

8 yellow and 3 red

You can check your answers with the Adding It Up: Get It Answer Key (Downloadable Resources).

For more information on this topic, watch the following video.

 Now that you have gotten a handle on how to add rational numbers using counters, take it to the next level and build your skills even more in the Got It? section.