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 11 to make 50?
11 · 50 · Complements to 10, 20 & 100
2. How many more do you need to add to 15 to make 30?
15 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 75 to make 100?
75 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 8 to make 50?
8 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 20 to make 30?
20 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 20 to make 50?
20 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 12 to make 20?
12 · 20 · Complements to 10, 20 & 100
11. How many more do you need to add to 16 to make 100?
16 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104730 · 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 11 to make 50?
39
Subtract 11 from 50: 50 − 11 = 39.
2. How many more do you need to add to 15 to make 30?
15
Subtract 15 from 30: 30 − 15 = 15.
3. How many more do you need to add to 75 to make 100?
25
Subtract 75 from 100: 100 − 75 = 25.
4. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
5. How many more do you need to add to 8 to make 50?
42
Subtract 8 from 50: 50 − 8 = 42.
6. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
7. How many more do you need to add to 20 to make 30?
10
Subtract 20 from 30: 30 − 20 = 10.
8. How many more do you need to add to 20 to make 50?
30
Subtract 20 from 50: 50 − 20 = 30.
9. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
10. How many more do you need to add to 12 to make 20?
8
Subtract 12 from 20: 20 − 12 = 8.
11. How many more do you need to add to 16 to make 100?
84
Subtract 16 from 100: 100 − 16 = 84.
12. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.

12 questions · Seed 104730 · 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 11 to make 50?
11 · 50 · Complements to 10, 20 & 100
2. How many more do you need to add to 15 to make 30?
15 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 75 to make 100?
75 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 8 to make 50?
8 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 20 to make 30?
20 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 20 to make 50?
20 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 12 to make 20?
12 · 20 · Complements to 10, 20 & 100
11. How many more do you need to add to 16 to make 100?
16 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104730 · 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 11 to make 50?
39
Subtract 11 from 50: 50 − 11 = 39.
2. How many more do you need to add to 15 to make 30?
15
Subtract 15 from 30: 30 − 15 = 15.
3. How many more do you need to add to 75 to make 100?
25
Subtract 75 from 100: 100 − 75 = 25.
4. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
5. How many more do you need to add to 8 to make 50?
42
Subtract 8 from 50: 50 − 8 = 42.
6. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
7. How many more do you need to add to 20 to make 30?
10
Subtract 20 from 30: 30 − 20 = 10.
8. How many more do you need to add to 20 to make 50?
30
Subtract 20 from 50: 50 − 20 = 30.
9. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
10. How many more do you need to add to 12 to make 20?
8
Subtract 12 from 20: 20 − 12 = 8.
11. How many more do you need to add to 16 to make 100?
84
Subtract 16 from 100: 100 − 16 = 84.
12. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.

12 questions · Seed 104730 · Age guidance, not curriculum certification