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 15 to make 30?
15 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 9 to make 30?
9 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 7 to make 20?
7 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 4 to make 20?
4 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 16 to make 100?
16 · 100 · Complements to 10, 20 & 100
7. How many more do you need to add to 13 to make 20?
13 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 16 to make 50?
16 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 7 to make 30?
7 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 84 to make 100?
84 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104758 · 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 15 to make 30?
15
Subtract 15 from 30: 30 − 15 = 15.
2. How many more do you need to add to 9 to make 30?
21
Subtract 9 from 30: 30 − 9 = 21.
3. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
4. How many more do you need to add to 7 to make 20?
13
Subtract 7 from 20: 20 − 7 = 13.
5. How many more do you need to add to 4 to make 20?
16
Subtract 4 from 20: 20 − 4 = 16.
6. How many more do you need to add to 16 to make 100?
84
Subtract 16 from 100: 100 − 16 = 84.
7. How many more do you need to add to 13 to make 20?
7
Subtract 13 from 20: 20 − 13 = 7.
8. How many more do you need to add to 16 to make 50?
34
Subtract 16 from 50: 50 − 16 = 34.
9. How many more do you need to add to 7 to make 30?
23
Subtract 7 from 30: 30 − 7 = 23.
10. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
11. How many more do you need to add to 84 to make 100?
16
Subtract 84 from 100: 100 − 84 = 16.
12. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.

12 questions · Seed 104758 · 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 15 to make 30?
15 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 9 to make 30?
9 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 7 to make 20?
7 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 4 to make 20?
4 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 16 to make 100?
16 · 100 · Complements to 10, 20 & 100
7. How many more do you need to add to 13 to make 20?
13 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 16 to make 50?
16 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 7 to make 30?
7 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 84 to make 100?
84 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104758 · 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 15 to make 30?
15
Subtract 15 from 30: 30 − 15 = 15.
2. How many more do you need to add to 9 to make 30?
21
Subtract 9 from 30: 30 − 9 = 21.
3. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
4. How many more do you need to add to 7 to make 20?
13
Subtract 7 from 20: 20 − 7 = 13.
5. How many more do you need to add to 4 to make 20?
16
Subtract 4 from 20: 20 − 4 = 16.
6. How many more do you need to add to 16 to make 100?
84
Subtract 16 from 100: 100 − 16 = 84.
7. How many more do you need to add to 13 to make 20?
7
Subtract 13 from 20: 20 − 13 = 7.
8. How many more do you need to add to 16 to make 50?
34
Subtract 16 from 50: 50 − 16 = 34.
9. How many more do you need to add to 7 to make 30?
23
Subtract 7 from 30: 30 − 7 = 23.
10. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
11. How many more do you need to add to 84 to make 100?
16
Subtract 84 from 100: 100 − 84 = 16.
12. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.

12 questions · Seed 104758 · Age guidance, not curriculum certification