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Thirty-one to fifty
Joyful Mathematics: Chapter 8
GoalCount and write the numbers from 31 to 50.
New words
forty · the name for 4 tens, written 40fifty · the name for 5 tens, written 50after · the next number
Explanation
After 30 the tens keep growing. 3 tens and 6 ones make 36, thirty-six. 4 tens make 40, forty. 5 tens make 50, fifty. A number just after 40 is called forty-one, forty-two and so on. We write 43 for forty-three.
Worked examples
3 tens and 6 ones make thirty-six.
4 tens and 7 ones make forty-seven.
4 tens and no ones make forty.
Class activity
Clap and stamp. Count 10, 20, 30, 40, 50 and clap each time. Then count from 41 to 50 and stamp your feet on every number. Try again with a friend, one number each.
Practice
1
Look at the blocks. Which number is this?
43
2
What comes after 39?
40
3
What comes just before 50?
49
4
Write forty-five as a number.
45
5
How many tens are in 38?
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