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 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 29 to make 50?
29 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 25 to make 50?
25 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 9 to make 50?
9 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 14 to make 30?
14 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 1 to make 100?
1 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 49 to make 50?
49 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 17 to make 20?
17 · 20 · Complements to 10, 20 & 100
12. How many more do you need to add to 5 to make 30?
5 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104774 · 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 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
2. How many more do you need to add to 29 to make 50?
21
Subtract 29 from 50: 50 − 29 = 21.
3. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
4. How many more do you need to add to 25 to make 50?
25
Subtract 25 from 50: 50 − 25 = 25.
5. How many more do you need to add to 9 to make 50?
41
Subtract 9 from 50: 50 − 9 = 41.
6. How many more do you need to add to 14 to make 30?
16
Subtract 14 from 30: 30 − 14 = 16.
7. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
8. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.
9. How many more do you need to add to 1 to make 100?
99
Subtract 1 from 100: 100 − 1 = 99.
10. How many more do you need to add to 49 to make 50?
1
Subtract 49 from 50: 50 − 49 = 1.
11. How many more do you need to add to 17 to make 20?
3
Subtract 17 from 20: 20 − 17 = 3.
12. How many more do you need to add to 5 to make 30?
25
Subtract 5 from 30: 30 − 5 = 25.

12 questions · Seed 104774 · 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 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 29 to make 50?
29 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 25 to make 50?
25 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 9 to make 50?
9 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 14 to make 30?
14 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 1 to make 100?
1 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 49 to make 50?
49 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 17 to make 20?
17 · 20 · Complements to 10, 20 & 100
12. How many more do you need to add to 5 to make 30?
5 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104774 · 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 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
2. How many more do you need to add to 29 to make 50?
21
Subtract 29 from 50: 50 − 29 = 21.
3. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
4. How many more do you need to add to 25 to make 50?
25
Subtract 25 from 50: 50 − 25 = 25.
5. How many more do you need to add to 9 to make 50?
41
Subtract 9 from 50: 50 − 9 = 41.
6. How many more do you need to add to 14 to make 30?
16
Subtract 14 from 30: 30 − 14 = 16.
7. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
8. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.
9. How many more do you need to add to 1 to make 100?
99
Subtract 1 from 100: 100 − 1 = 99.
10. How many more do you need to add to 49 to make 50?
1
Subtract 49 from 50: 50 − 49 = 1.
11. How many more do you need to add to 17 to make 20?
3
Subtract 17 from 20: 20 − 17 = 3.
12. How many more do you need to add to 5 to make 30?
25
Subtract 5 from 30: 30 − 5 = 25.

12 questions · Seed 104774 · Age guidance, not curriculum certification