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 4 to make 100?
4 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 12 to make 20?
12 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 8 to make 50?
8 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 7 to make 50?
7 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 12 to make 30?
12 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 2 to make 50?
2 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 29 to make 50?
29 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 29 to make 30?
29 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 21 to make 50?
21 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 46 to make 100?
46 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104762 · 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 4 to make 100?
96
Subtract 4 from 100: 100 − 4 = 96.
2. How many more do you need to add to 12 to make 20?
8
Subtract 12 from 20: 20 − 12 = 8.
3. How many more do you need to add to 8 to make 50?
42
Subtract 8 from 50: 50 − 8 = 42.
4. How many more do you need to add to 7 to make 50?
43
Subtract 7 from 50: 50 − 7 = 43.
5. How many more do you need to add to 12 to make 30?
18
Subtract 12 from 30: 30 − 12 = 18.
6. How many more do you need to add to 2 to make 50?
48
Subtract 2 from 50: 50 − 2 = 48.
7. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
8. How many more do you need to add to 29 to make 50?
21
Subtract 29 from 50: 50 − 29 = 21.
9. How many more do you need to add to 29 to make 30?
1
Subtract 29 from 30: 30 − 29 = 1.
10. How many more do you need to add to 21 to make 50?
29
Subtract 21 from 50: 50 − 21 = 29.
11. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
12. How many more do you need to add to 46 to make 100?
54
Subtract 46 from 100: 100 − 46 = 54.

12 questions · Seed 104762 · 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 4 to make 100?
4 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 12 to make 20?
12 · 20 · Complements to 10, 20 & 100
3. How many more do you need to add to 8 to make 50?
8 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 7 to make 50?
7 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 12 to make 30?
12 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 2 to make 50?
2 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 29 to make 50?
29 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 29 to make 30?
29 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 21 to make 50?
21 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 46 to make 100?
46 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104762 · 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 4 to make 100?
96
Subtract 4 from 100: 100 − 4 = 96.
2. How many more do you need to add to 12 to make 20?
8
Subtract 12 from 20: 20 − 12 = 8.
3. How many more do you need to add to 8 to make 50?
42
Subtract 8 from 50: 50 − 8 = 42.
4. How many more do you need to add to 7 to make 50?
43
Subtract 7 from 50: 50 − 7 = 43.
5. How many more do you need to add to 12 to make 30?
18
Subtract 12 from 30: 30 − 12 = 18.
6. How many more do you need to add to 2 to make 50?
48
Subtract 2 from 50: 50 − 2 = 48.
7. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
8. How many more do you need to add to 29 to make 50?
21
Subtract 29 from 50: 50 − 29 = 21.
9. How many more do you need to add to 29 to make 30?
1
Subtract 29 from 30: 30 − 29 = 1.
10. How many more do you need to add to 21 to make 50?
29
Subtract 21 from 50: 50 − 21 = 29.
11. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
12. How many more do you need to add to 46 to make 100?
54
Subtract 46 from 100: 100 − 46 = 54.

12 questions · Seed 104762 · Age guidance, not curriculum certification