10 More, 10 Less

Find 10 more or 10 less without counting.

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

What children learn in Level 33

10 more than 34: add one ten. 3 tens becomes 4 tens, and the 4 ones don't change. 44!
On the hundred chart, 10 more is one step straight down. 10 less is one step straight up.
Your turn! Tap the number that is 10 more than 67.
There were 74 birds in the park. 10 flew away. Picture 7 tens and 4 ones. Take away one ten: 6 tens and 4 ones. 64 birds!
10 more or 10 less: only the tens digit changes, by one. No counting needed!

Georgia's K-12 Mathematics Standards:

1.NR.5.2 — Given a two-digit number, mentally find 10 more or 10 less than the number, without having to count; explain the reasoning used.