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 48 to make 100?
48 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 37 to make 100?
37 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 42 to make 50?
42 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 1 to make 20?
1 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 2 to make 20?
2 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 12 to make 30?
12 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 8 to make 30?
8 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 97 to make 100?
97 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 26 to make 50?
26 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 57 to make 100?
57 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 22 to make 30?
22 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104767 · 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 48 to make 100?
52
Subtract 48 from 100: 100 − 48 = 52.
2. How many more do you need to add to 37 to make 100?
63
Subtract 37 from 100: 100 − 37 = 63.
3. How many more do you need to add to 42 to make 50?
8
Subtract 42 from 50: 50 − 42 = 8.
4. How many more do you need to add to 1 to make 20?
19
Subtract 1 from 20: 20 − 1 = 19.
5. How many more do you need to add to 2 to make 20?
18
Subtract 2 from 20: 20 − 2 = 18.
6. How many more do you need to add to 12 to make 30?
18
Subtract 12 from 30: 30 − 12 = 18.
7. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
8. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
9. How many more do you need to add to 97 to make 100?
3
Subtract 97 from 100: 100 − 97 = 3.
10. How many more do you need to add to 26 to make 50?
24
Subtract 26 from 50: 50 − 26 = 24.
11. How many more do you need to add to 57 to make 100?
43
Subtract 57 from 100: 100 − 57 = 43.
12. How many more do you need to add to 22 to make 30?
8
Subtract 22 from 30: 30 − 22 = 8.

12 questions · Seed 104767 · 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 48 to make 100?
48 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 37 to make 100?
37 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 42 to make 50?
42 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 1 to make 20?
1 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 2 to make 20?
2 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 12 to make 30?
12 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 8 to make 30?
8 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 97 to make 100?
97 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 26 to make 50?
26 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 57 to make 100?
57 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 22 to make 30?
22 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104767 · 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 48 to make 100?
52
Subtract 48 from 100: 100 − 48 = 52.
2. How many more do you need to add to 37 to make 100?
63
Subtract 37 from 100: 100 − 37 = 63.
3. How many more do you need to add to 42 to make 50?
8
Subtract 42 from 50: 50 − 42 = 8.
4. How many more do you need to add to 1 to make 20?
19
Subtract 1 from 20: 20 − 1 = 19.
5. How many more do you need to add to 2 to make 20?
18
Subtract 2 from 20: 20 − 2 = 18.
6. How many more do you need to add to 12 to make 30?
18
Subtract 12 from 30: 30 − 12 = 18.
7. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
8. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
9. How many more do you need to add to 97 to make 100?
3
Subtract 97 from 100: 100 − 97 = 3.
10. How many more do you need to add to 26 to make 50?
24
Subtract 26 from 50: 50 − 26 = 24.
11. How many more do you need to add to 57 to make 100?
43
Subtract 57 from 100: 100 − 57 = 43.
12. How many more do you need to add to 22 to make 30?
8
Subtract 22 from 30: 30 − 22 = 8.

12 questions · Seed 104767 · Age guidance, not curriculum certification