Addition and subtraction strategies
Use counting on and counting back as strategies for addition and subtraction
What a learner can do afterwards
- Add 8 + 3 by starting at 8 and counting on 3 (9, 10, 11)
- Subtract 12 − 3 by counting back 3 from 12 (11, 10, 9)
- Explain that counting on is a way to add
The lesson
You already know how to add and take away. Here is a quick trick for both: counting on and counting back. Instead of starting from 1 every time, you start at one number and hop forward or backward.
Leo has 12 stickers and gives away 3. He starts at 12 and counts back three hops: 11, 10, 9. Leo has 9 stickers left.
When you add, start at the bigger number. That means fewer hops to count. Say each number out loud as you hop so you do not lose your place.
Counting on adds by hopping forward, and counting back subtracts by hopping backward, from one starting number.
Watch it
Where it sits
Learn first
This opens up
Nothing builds on it yet.
Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.