Counting On and Counting Back

Add by counting on and subtract by counting back.

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

What children learn in Level 34

To add, start with the bigger number and count on. 6 plus 3: say 6, then count on 3 more: 7, 8, 9.
To take away, start with the first number and count back. 8 minus 3: say 8, then count back 3: 7, 6, 5.
Your turn! 2 plus 5: start at 5, the bigger number. Tap the number line to count on 2.
Your turn! 9 minus 2: start at 9. Tap the number line to count back 2.
Stories can be written as number sentences. 3 birds, and 2 more came: 3 plus 2. 5 birds, and 2 flew away: 5 minus 2.
Try it with a grown-up! Walk on a number line made of steps or tiles. Count on to add, and step back to take away.

Georgia's K-12 Mathematics Standards:

K.NR.5.2 — Represent addition and subtraction within 10 from a given authentic situation using a variety of representations and strategies.
K.NR.5.3 — Use a variety of strategies to solve addition and subtraction problems within 10.