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 17 to make 30?
17 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 46 to make 100?
46 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 13 to make 50?
13 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 79 to make 100?
79 · 100 · Complements to 10, 20 & 100
6. How many more do you need to add to 29 to make 100?
29 · 100 · Complements to 10, 20 & 100
7. How many more do you need to add to 3 to make 30?
3 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 52 to make 100?
52 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 14 to make 30?
14 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104760 · 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 17 to make 30?
13
Subtract 17 from 30: 30 − 17 = 13.
2. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
3. How many more do you need to add to 46 to make 100?
54
Subtract 46 from 100: 100 − 46 = 54.
4. How many more do you need to add to 13 to make 50?
37
Subtract 13 from 50: 50 − 13 = 37.
5. How many more do you need to add to 79 to make 100?
21
Subtract 79 from 100: 100 − 79 = 21.
6. How many more do you need to add to 29 to make 100?
71
Subtract 29 from 100: 100 − 29 = 71.
7. How many more do you need to add to 3 to make 30?
27
Subtract 3 from 30: 30 − 3 = 27.
8. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
9. How many more do you need to add to 52 to make 100?
48
Subtract 52 from 100: 100 − 52 = 48.
10. How many more do you need to add to 14 to make 30?
16
Subtract 14 from 30: 30 − 14 = 16.
11. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
12. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.

12 questions · Seed 104760 · 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 17 to make 30?
17 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 46 to make 100?
46 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 13 to make 50?
13 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 79 to make 100?
79 · 100 · Complements to 10, 20 & 100
6. How many more do you need to add to 29 to make 100?
29 · 100 · Complements to 10, 20 & 100
7. How many more do you need to add to 3 to make 30?
3 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 52 to make 100?
52 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 14 to make 30?
14 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104760 · 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 17 to make 30?
13
Subtract 17 from 30: 30 − 17 = 13.
2. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
3. How many more do you need to add to 46 to make 100?
54
Subtract 46 from 100: 100 − 46 = 54.
4. How many more do you need to add to 13 to make 50?
37
Subtract 13 from 50: 50 − 13 = 37.
5. How many more do you need to add to 79 to make 100?
21
Subtract 79 from 100: 100 − 79 = 21.
6. How many more do you need to add to 29 to make 100?
71
Subtract 29 from 100: 100 − 29 = 71.
7. How many more do you need to add to 3 to make 30?
27
Subtract 3 from 30: 30 − 3 = 27.
8. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
9. How many more do you need to add to 52 to make 100?
48
Subtract 52 from 100: 100 − 52 = 48.
10. How many more do you need to add to 14 to make 30?
16
Subtract 14 from 30: 30 − 14 = 16.
11. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
12. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.

12 questions · Seed 104760 · Age guidance, not curriculum certification