Count On, Count Back

Add or take away 1, 2, or 3 by counting on or back from the bigger number.

Warm-up, learn, try it together, practice, then a quick check. About 15 minutes.

What children learn in Level 1

When you add a small number, you don't have to count everything. Start at the bigger number and count on!
Start at 8. Count on 3: 9, 10, 11. So 8 plus 3 is 11.
Your turn! Start at 9 and tap the number line to count on 2 more.
What about 2 plus 9? Start at the bigger number, 9, and count on 2. It's 11 either way!
To take away a small number, count back. 12 minus 3: start at 12 and count back 11, 10, 9.
Your turn! Start at 15 and tap to count back 2.
Count on to add. Count back to take away. Let's try some!

Georgia's K-12 Mathematics Standards:

2.NR.2.1 — Fluently add and subtract within 20 using a variety of mental, part-whole strategies.