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 55 to make 100?
55 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 13 to make 50?
13 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 79 to make 100?
79 · 100 · Complements to 10, 20 & 100
5. How many more do you need to add to 5 to make 20?
5 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 17 to make 30?
17 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 11 to make 50?
11 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 2 to make 30?
2 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 14 to make 100?
14 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 12 to make 100?
12 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 73 to make 100?
73 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 59 to make 100?
59 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104787 · 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 55 to make 100?
45
Subtract 55 from 100: 100 − 55 = 45.
2. How many more do you need to add to 13 to make 50?
37
Subtract 13 from 50: 50 − 13 = 37.
3. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
4. How many more do you need to add to 79 to make 100?
21
Subtract 79 from 100: 100 − 79 = 21.
5. How many more do you need to add to 5 to make 20?
15
Subtract 5 from 20: 20 − 5 = 15.
6. How many more do you need to add to 17 to make 30?
13
Subtract 17 from 30: 30 − 17 = 13.
7. How many more do you need to add to 11 to make 50?
39
Subtract 11 from 50: 50 − 11 = 39.
8. How many more do you need to add to 2 to make 30?
28
Subtract 2 from 30: 30 − 2 = 28.
9. How many more do you need to add to 14 to make 100?
86
Subtract 14 from 100: 100 − 14 = 86.
10. How many more do you need to add to 12 to make 100?
88
Subtract 12 from 100: 100 − 12 = 88.
11. How many more do you need to add to 73 to make 100?
27
Subtract 73 from 100: 100 − 73 = 27.
12. How many more do you need to add to 59 to make 100?
41
Subtract 59 from 100: 100 − 59 = 41.

12 questions · Seed 104787 · 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 55 to make 100?
55 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 13 to make 50?
13 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 79 to make 100?
79 · 100 · Complements to 10, 20 & 100
5. How many more do you need to add to 5 to make 20?
5 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 17 to make 30?
17 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 11 to make 50?
11 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 2 to make 30?
2 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 14 to make 100?
14 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 12 to make 100?
12 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 73 to make 100?
73 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 59 to make 100?
59 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104787 · 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 55 to make 100?
45
Subtract 55 from 100: 100 − 55 = 45.
2. How many more do you need to add to 13 to make 50?
37
Subtract 13 from 50: 50 − 13 = 37.
3. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
4. How many more do you need to add to 79 to make 100?
21
Subtract 79 from 100: 100 − 79 = 21.
5. How many more do you need to add to 5 to make 20?
15
Subtract 5 from 20: 20 − 5 = 15.
6. How many more do you need to add to 17 to make 30?
13
Subtract 17 from 30: 30 − 17 = 13.
7. How many more do you need to add to 11 to make 50?
39
Subtract 11 from 50: 50 − 11 = 39.
8. How many more do you need to add to 2 to make 30?
28
Subtract 2 from 30: 30 − 2 = 28.
9. How many more do you need to add to 14 to make 100?
86
Subtract 14 from 100: 100 − 14 = 86.
10. How many more do you need to add to 12 to make 100?
88
Subtract 12 from 100: 100 − 12 = 88.
11. How many more do you need to add to 73 to make 100?
27
Subtract 73 from 100: 100 − 73 = 27.
12. How many more do you need to add to 59 to make 100?
41
Subtract 59 from 100: 100 − 59 = 41.

12 questions · Seed 104787 · Age guidance, not curriculum certification