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 42 to make 50?
42 · 50 · Complements to 10, 20 & 100
2. How many more do you need to add to 75 to make 100?
75 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 95 to make 100?
95 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 6 to make 100?
6 · 100 · Complements to 10, 20 & 100
6. How many more do you need to add to 12 to make 50?
12 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 91 to make 100?
91 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 11 to make 20?
11 · 20 · Complements to 10, 20 & 100
10. How many more do you need to add to 11 to make 100?
11 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
12. How many more do you need to add to 22 to make 50?
22 · 50 · Complements to 10, 20 & 100

12 questions · Seed 104772 · 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 42 to make 50?
8
Subtract 42 from 50: 50 − 42 = 8.
2. How many more do you need to add to 75 to make 100?
25
Subtract 75 from 100: 100 − 75 = 25.
3. How many more do you need to add to 95 to make 100?
5
Subtract 95 from 100: 100 − 95 = 5.
4. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
5. How many more do you need to add to 6 to make 100?
94
Subtract 6 from 100: 100 − 6 = 94.
6. How many more do you need to add to 12 to make 50?
38
Subtract 12 from 50: 50 − 12 = 38.
7. How many more do you need to add to 91 to make 100?
9
Subtract 91 from 100: 100 − 91 = 9.
8. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
9. How many more do you need to add to 11 to make 20?
9
Subtract 11 from 20: 20 − 11 = 9.
10. How many more do you need to add to 11 to make 100?
89
Subtract 11 from 100: 100 − 11 = 89.
11. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
12. How many more do you need to add to 22 to make 50?
28
Subtract 22 from 50: 50 − 22 = 28.

12 questions · Seed 104772 · 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 42 to make 50?
42 · 50 · Complements to 10, 20 & 100
2. How many more do you need to add to 75 to make 100?
75 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 95 to make 100?
95 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 6 to make 100?
6 · 100 · Complements to 10, 20 & 100
6. How many more do you need to add to 12 to make 50?
12 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 91 to make 100?
91 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 11 to make 20?
11 · 20 · Complements to 10, 20 & 100
10. How many more do you need to add to 11 to make 100?
11 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
12. How many more do you need to add to 22 to make 50?
22 · 50 · Complements to 10, 20 & 100

12 questions · Seed 104772 · 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 42 to make 50?
8
Subtract 42 from 50: 50 − 42 = 8.
2. How many more do you need to add to 75 to make 100?
25
Subtract 75 from 100: 100 − 75 = 25.
3. How many more do you need to add to 95 to make 100?
5
Subtract 95 from 100: 100 − 95 = 5.
4. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
5. How many more do you need to add to 6 to make 100?
94
Subtract 6 from 100: 100 − 6 = 94.
6. How many more do you need to add to 12 to make 50?
38
Subtract 12 from 50: 50 − 12 = 38.
7. How many more do you need to add to 91 to make 100?
9
Subtract 91 from 100: 100 − 91 = 9.
8. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
9. How many more do you need to add to 11 to make 20?
9
Subtract 11 from 20: 20 − 11 = 9.
10. How many more do you need to add to 11 to make 100?
89
Subtract 11 from 100: 100 − 11 = 89.
11. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
12. How many more do you need to add to 22 to make 50?
28
Subtract 22 from 50: 50 − 22 = 28.

12 questions · Seed 104772 · Age guidance, not curriculum certification