1
Count up to 20 things
Learner’s Book 1: Unit 9, pp. 123–126
GoalCount up to 20 objects by seeing a full ten and counting on.
New words
count on · start at a number and keep countingdigit · one number sign, 0 to 9ten frame · a box that holds 10 things
Explanation
To count up to 20 things, we do not always count from 1. We can look for a full ten. A full ten frame holds 10. Then we count on from 10 for the rest. If a full frame has 10 and the next frame has 7, we say: 10, 11, 12, 13, 14, 15, 16, 17. There are 17. Numbers are made with digits. The number 17 uses the digits 1 and 7. The 1 stands for one ten and the 7 stands for seven ones.
Worked examples
Count the counters on the frames. The first frame is full: 10. Count on: 11, 12, 13, 14, 15, 16. There are 16 counters.
A row of 10 balls and 8 more balls below. 10, then count on: 11, 12, 13, 14, 15, 16, 17, 18. There are 18 balls.
The number 18 uses two digits: 1 and 8. The 1 means a ten and the 8 means 8 ones.
Class activity
Pen count: take 15 to 20 pencils, crayons or spoons. Put 10 in a pile and count the rest by counting on from 10. Then count again from 1 to check. Do you get the same number?
Practice
1
How many counters are on the frames?
13
2
How many pencils are there?
19
3
You want to show 15 on two ten frames. How many counters go in each frame?
10 in the first frame and 5 in the second.
4
How many digits does the number 13 have?
2 (the digits 1 and 3)