3
Review: ten and up to 20
Joyful Mathematics: Chapters 1–4
GoalRevise pairs that make 10, and the numbers from 11 to 20.
New words
make 10 · two parts that join to give 10ten and ones · a full ten and some moretwenty · two tens, 20
Explanation
Two numbers can make 10. 3 and 7 make 10. 6 and 4 make 10. 5 and 5 make 10. After ten come eleven, twelve and on to twenty. 10 and 2 is 12. 10 and 9 is 19. 10 and 10 is 20. A bigger number is further along the number row.
Worked examples
10 and 2 is 12.
10 and 9 is 19. One more is 20.
Find the hidden numbers: 16 and 19.
Class activity
Race to twenty. Take turns to roll a dice and say the number. Add that many buttons to a pile and say how many buttons there are. The first to reach 20 or more wins. At 10, make a group of ten.
Practice
1
How many lotus flowers are there?
18.
2
6 dots are in the frame. How many more make 10?
4.
3
What comes after 14?
15.
4
Which is bigger, 13 or 19?
19.
5
What is the biggest of 17, 12 and 20?
20.