MathsAges 7-9

Complements to 10, 20 & 100

Find how many more are needed to complete a benchmark number such as 10, 20, 50 or 100. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

1. How many more do you need to add to 34 to make 100?
34 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 43 to make 50?
43 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 9 to make 50?
9 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 20 to make 30?
20 · 30 · Complements to 10, 20 & 100
5. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 47 to make 50?
47 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 39 to make 50?
39 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 28 to make 100?
28 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 1 to make 30?
1 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 22 to make 50?
22 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 21 to make 30?
21 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104744 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 7-9

Answers and reasoning. Review before teaching.

1. How many more do you need to add to 34 to make 100?
66
Subtract 34 from 100: 100 − 34 = 66.
2. How many more do you need to add to 43 to make 50?
7
Subtract 43 from 50: 50 − 43 = 7.
3. How many more do you need to add to 9 to make 50?
41
Subtract 9 from 50: 50 − 9 = 41.
4. How many more do you need to add to 20 to make 30?
10
Subtract 20 from 30: 30 − 20 = 10.
5. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
6. How many more do you need to add to 47 to make 50?
3
Subtract 47 from 50: 50 − 47 = 3.
7. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
8. How many more do you need to add to 39 to make 50?
11
Subtract 39 from 50: 50 − 39 = 11.
9. How many more do you need to add to 28 to make 100?
72
Subtract 28 from 100: 100 − 28 = 72.
10. How many more do you need to add to 1 to make 30?
29
Subtract 1 from 30: 30 − 1 = 29.
11. How many more do you need to add to 22 to make 50?
28
Subtract 22 from 50: 50 − 22 = 28.
12. How many more do you need to add to 21 to make 30?
9
Subtract 21 from 30: 30 − 21 = 9.

12 questions · Seed 104744 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

1. How many more do you need to add to 34 to make 100?
34 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 43 to make 50?
43 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 9 to make 50?
9 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 20 to make 30?
20 · 30 · Complements to 10, 20 & 100
5. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 47 to make 50?
47 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 39 to make 50?
39 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 28 to make 100?
28 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 1 to make 30?
1 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 22 to make 50?
22 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 21 to make 30?
21 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104744 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 7-9

Answers and reasoning. Review before teaching.

1. How many more do you need to add to 34 to make 100?
66
Subtract 34 from 100: 100 − 34 = 66.
2. How many more do you need to add to 43 to make 50?
7
Subtract 43 from 50: 50 − 43 = 7.
3. How many more do you need to add to 9 to make 50?
41
Subtract 9 from 50: 50 − 9 = 41.
4. How many more do you need to add to 20 to make 30?
10
Subtract 20 from 30: 30 − 20 = 10.
5. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
6. How many more do you need to add to 47 to make 50?
3
Subtract 47 from 50: 50 − 47 = 3.
7. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
8. How many more do you need to add to 39 to make 50?
11
Subtract 39 from 50: 50 − 39 = 11.
9. How many more do you need to add to 28 to make 100?
72
Subtract 28 from 100: 100 − 28 = 72.
10. How many more do you need to add to 1 to make 30?
29
Subtract 1 from 30: 30 − 1 = 29.
11. How many more do you need to add to 22 to make 50?
28
Subtract 22 from 50: 50 − 22 = 28.
12. How many more do you need to add to 21 to make 30?
9
Subtract 21 from 30: 30 − 21 = 9.

12 questions · Seed 104744 · Age guidance, not curriculum certification