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 24 to make 30?
24 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 19 to make 100?
19 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 59 to make 100?
59 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 12 to make 50?
12 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 17 to make 30?
17 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 33 to make 100?
33 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 52 to make 100?
52 · 100 · Complements to 10, 20 & 100
9. How many more do you need to add to 17 to make 50?
17 · 50 · Complements to 10, 20 & 100
10. How many more do you need to add to 30 to make 100?
30 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 38 to make 100?
38 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 12 to make 30?
12 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104784 · 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 24 to make 30?
6
Subtract 24 from 30: 30 − 24 = 6.
2. How many more do you need to add to 19 to make 100?
81
Subtract 19 from 100: 100 − 19 = 81.
3. How many more do you need to add to 59 to make 100?
41
Subtract 59 from 100: 100 − 59 = 41.
4. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
5. How many more do you need to add to 12 to make 50?
38
Subtract 12 from 50: 50 − 12 = 38.
6. How many more do you need to add to 17 to make 30?
13
Subtract 17 from 30: 30 − 17 = 13.
7. How many more do you need to add to 33 to make 100?
67
Subtract 33 from 100: 100 − 33 = 67.
8. How many more do you need to add to 52 to make 100?
48
Subtract 52 from 100: 100 − 52 = 48.
9. How many more do you need to add to 17 to make 50?
33
Subtract 17 from 50: 50 − 17 = 33.
10. How many more do you need to add to 30 to make 100?
70
Subtract 30 from 100: 100 − 30 = 70.
11. How many more do you need to add to 38 to make 100?
62
Subtract 38 from 100: 100 − 38 = 62.
12. How many more do you need to add to 12 to make 30?
18
Subtract 12 from 30: 30 − 12 = 18.

12 questions · Seed 104784 · 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 24 to make 30?
24 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 19 to make 100?
19 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 59 to make 100?
59 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 12 to make 50?
12 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 17 to make 30?
17 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 33 to make 100?
33 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 52 to make 100?
52 · 100 · Complements to 10, 20 & 100
9. How many more do you need to add to 17 to make 50?
17 · 50 · Complements to 10, 20 & 100
10. How many more do you need to add to 30 to make 100?
30 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 38 to make 100?
38 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 12 to make 30?
12 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104784 · 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 24 to make 30?
6
Subtract 24 from 30: 30 − 24 = 6.
2. How many more do you need to add to 19 to make 100?
81
Subtract 19 from 100: 100 − 19 = 81.
3. How many more do you need to add to 59 to make 100?
41
Subtract 59 from 100: 100 − 59 = 41.
4. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
5. How many more do you need to add to 12 to make 50?
38
Subtract 12 from 50: 50 − 12 = 38.
6. How many more do you need to add to 17 to make 30?
13
Subtract 17 from 30: 30 − 17 = 13.
7. How many more do you need to add to 33 to make 100?
67
Subtract 33 from 100: 100 − 33 = 67.
8. How many more do you need to add to 52 to make 100?
48
Subtract 52 from 100: 100 − 52 = 48.
9. How many more do you need to add to 17 to make 50?
33
Subtract 17 from 50: 50 − 17 = 33.
10. How many more do you need to add to 30 to make 100?
70
Subtract 30 from 100: 100 − 30 = 70.
11. How many more do you need to add to 38 to make 100?
62
Subtract 38 from 100: 100 − 38 = 62.
12. How many more do you need to add to 12 to make 30?
18
Subtract 12 from 30: 30 − 12 = 18.

12 questions · Seed 104784 · Age guidance, not curriculum certification