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 46 to make 100?
46 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 21 to make 30?
21 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 23 to make 50?
23 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 44 to make 50?
44 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 22 to make 100?
22 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 85 to make 100?
85 · 100 · Complements to 10, 20 & 100
9. How many more do you need to add to 1 to make 30?
1 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 41 to make 50?
41 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104788 · 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 46 to make 100?
54
Subtract 46 from 100: 100 − 46 = 54.
2. How many more do you need to add to 21 to make 30?
9
Subtract 21 from 30: 30 − 21 = 9.
3. How many more do you need to add to 23 to make 50?
27
Subtract 23 from 50: 50 − 23 = 27.
4. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
5. How many more do you need to add to 44 to make 50?
6
Subtract 44 from 50: 50 − 44 = 6.
6. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
7. How many more do you need to add to 22 to make 100?
78
Subtract 22 from 100: 100 − 22 = 78.
8. How many more do you need to add to 85 to make 100?
15
Subtract 85 from 100: 100 − 85 = 15.
9. How many more do you need to add to 1 to make 30?
29
Subtract 1 from 30: 30 − 1 = 29.
10. How many more do you need to add to 41 to make 50?
9
Subtract 41 from 50: 50 − 41 = 9.
11. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
12. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.

12 questions · Seed 104788 · 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 46 to make 100?
46 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 21 to make 30?
21 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 23 to make 50?
23 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 44 to make 50?
44 · 50 · Complements to 10, 20 & 100
6. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 22 to make 100?
22 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 85 to make 100?
85 · 100 · Complements to 10, 20 & 100
9. How many more do you need to add to 1 to make 30?
1 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 41 to make 50?
41 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
12. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104788 · 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 46 to make 100?
54
Subtract 46 from 100: 100 − 46 = 54.
2. How many more do you need to add to 21 to make 30?
9
Subtract 21 from 30: 30 − 21 = 9.
3. How many more do you need to add to 23 to make 50?
27
Subtract 23 from 50: 50 − 23 = 27.
4. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
5. How many more do you need to add to 44 to make 50?
6
Subtract 44 from 50: 50 − 44 = 6.
6. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
7. How many more do you need to add to 22 to make 100?
78
Subtract 22 from 100: 100 − 22 = 78.
8. How many more do you need to add to 85 to make 100?
15
Subtract 85 from 100: 100 − 85 = 15.
9. How many more do you need to add to 1 to make 30?
29
Subtract 1 from 30: 30 − 1 = 29.
10. How many more do you need to add to 41 to make 50?
9
Subtract 41 from 50: 50 − 41 = 9.
11. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
12. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.

12 questions · Seed 104788 · Age guidance, not curriculum certification