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 6 to make 30?
6 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 27 to make 30?
27 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 39 to make 100?
39 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 7 to make 20?
7 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100
7. How many more do you need to add to 2 to make 30?
2 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 18 to make 30?
18 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 62 to make 100?
62 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 40 to make 50?
40 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 7 to make 100?
7 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104742 · 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 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.
2. How many more do you need to add to 27 to make 30?
3
Subtract 27 from 30: 30 − 27 = 3.
3. How many more do you need to add to 39 to make 100?
61
Subtract 39 from 100: 100 − 39 = 61.
4. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
5. How many more do you need to add to 7 to make 20?
13
Subtract 7 from 20: 20 − 7 = 13.
6. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.
7. How many more do you need to add to 2 to make 30?
28
Subtract 2 from 30: 30 − 2 = 28.
8. How many more do you need to add to 18 to make 30?
12
Subtract 18 from 30: 30 − 18 = 12.
9. How many more do you need to add to 62 to make 100?
38
Subtract 62 from 100: 100 − 62 = 38.
10. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
11. How many more do you need to add to 40 to make 50?
10
Subtract 40 from 50: 50 − 40 = 10.
12. How many more do you need to add to 7 to make 100?
93
Subtract 7 from 100: 100 − 7 = 93.

12 questions · Seed 104742 · 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 6 to make 30?
6 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 27 to make 30?
27 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 39 to make 100?
39 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 46 to make 50?
46 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 7 to make 20?
7 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100
7. How many more do you need to add to 2 to make 30?
2 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 18 to make 30?
18 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 62 to make 100?
62 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 40 to make 50?
40 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 7 to make 100?
7 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104742 · 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 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.
2. How many more do you need to add to 27 to make 30?
3
Subtract 27 from 30: 30 − 27 = 3.
3. How many more do you need to add to 39 to make 100?
61
Subtract 39 from 100: 100 − 39 = 61.
4. How many more do you need to add to 46 to make 50?
4
Subtract 46 from 50: 50 − 46 = 4.
5. How many more do you need to add to 7 to make 20?
13
Subtract 7 from 20: 20 − 7 = 13.
6. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.
7. How many more do you need to add to 2 to make 30?
28
Subtract 2 from 30: 30 − 2 = 28.
8. How many more do you need to add to 18 to make 30?
12
Subtract 18 from 30: 30 − 18 = 12.
9. How many more do you need to add to 62 to make 100?
38
Subtract 62 from 100: 100 − 62 = 38.
10. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
11. How many more do you need to add to 40 to make 50?
10
Subtract 40 from 50: 50 − 40 = 10.
12. How many more do you need to add to 7 to make 100?
93
Subtract 7 from 100: 100 − 7 = 93.

12 questions · Seed 104742 · Age guidance, not curriculum certification