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 8 to make 50?
8 · 50 · Complements to 10, 20 & 100
2. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 4 to make 50?
4 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 54 to make 100?
54 · 100 · Complements to 10, 20 & 100
5. How many more do you need to add to 20 to make 30?
20 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 3 to make 50?
3 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 9 to make 30?
9 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 29 to make 30?
29 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 38 to make 100?
38 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 65 to make 100?
65 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 8 to make 30?
8 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 25 to make 50?
25 · 50 · Complements to 10, 20 & 100

12 questions · Seed 104739 · 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 8 to make 50?
42
Subtract 8 from 50: 50 − 8 = 42.
2. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.
3. How many more do you need to add to 4 to make 50?
46
Subtract 4 from 50: 50 − 4 = 46.
4. How many more do you need to add to 54 to make 100?
46
Subtract 54 from 100: 100 − 54 = 46.
5. How many more do you need to add to 20 to make 30?
10
Subtract 20 from 30: 30 − 20 = 10.
6. How many more do you need to add to 3 to make 50?
47
Subtract 3 from 50: 50 − 3 = 47.
7. How many more do you need to add to 9 to make 30?
21
Subtract 9 from 30: 30 − 9 = 21.
8. How many more do you need to add to 29 to make 30?
1
Subtract 29 from 30: 30 − 29 = 1.
9. How many more do you need to add to 38 to make 100?
62
Subtract 38 from 100: 100 − 38 = 62.
10. How many more do you need to add to 65 to make 100?
35
Subtract 65 from 100: 100 − 65 = 35.
11. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
12. How many more do you need to add to 25 to make 50?
25
Subtract 25 from 50: 50 − 25 = 25.

12 questions · Seed 104739 · 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 8 to make 50?
8 · 50 · Complements to 10, 20 & 100
2. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 4 to make 50?
4 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 54 to make 100?
54 · 100 · Complements to 10, 20 & 100
5. How many more do you need to add to 20 to make 30?
20 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 3 to make 50?
3 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 9 to make 30?
9 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 29 to make 30?
29 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 38 to make 100?
38 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 65 to make 100?
65 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 8 to make 30?
8 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 25 to make 50?
25 · 50 · Complements to 10, 20 & 100

12 questions · Seed 104739 · 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 8 to make 50?
42
Subtract 8 from 50: 50 − 8 = 42.
2. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.
3. How many more do you need to add to 4 to make 50?
46
Subtract 4 from 50: 50 − 4 = 46.
4. How many more do you need to add to 54 to make 100?
46
Subtract 54 from 100: 100 − 54 = 46.
5. How many more do you need to add to 20 to make 30?
10
Subtract 20 from 30: 30 − 20 = 10.
6. How many more do you need to add to 3 to make 50?
47
Subtract 3 from 50: 50 − 3 = 47.
7. How many more do you need to add to 9 to make 30?
21
Subtract 9 from 30: 30 − 9 = 21.
8. How many more do you need to add to 29 to make 30?
1
Subtract 29 from 30: 30 − 29 = 1.
9. How many more do you need to add to 38 to make 100?
62
Subtract 38 from 100: 100 − 38 = 62.
10. How many more do you need to add to 65 to make 100?
35
Subtract 65 from 100: 100 − 65 = 35.
11. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
12. How many more do you need to add to 25 to make 50?
25
Subtract 25 from 50: 50 − 25 = 25.

12 questions · Seed 104739 · Age guidance, not curriculum certification