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 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 14 to make 50?
14 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 5 to make 20?
5 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 18 to make 30?
18 · 30 · Complements to 10, 20 & 100
5. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 82 to make 100?
82 · 100 · Complements to 10, 20 & 100
7. How many more do you need to add to 21 to make 30?
21 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 7 to make 100?
7 · 100 · Complements to 10, 20 & 100
9. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
10. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
11. How many more do you need to add to 91 to make 100?
91 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100

12 questions · Seed 104734 · 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 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
2. How many more do you need to add to 14 to make 50?
36
Subtract 14 from 50: 50 − 14 = 36.
3. How many more do you need to add to 5 to make 20?
15
Subtract 5 from 20: 20 − 5 = 15.
4. How many more do you need to add to 18 to make 30?
12
Subtract 18 from 30: 30 − 18 = 12.
5. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
6. How many more do you need to add to 82 to make 100?
18
Subtract 82 from 100: 100 − 82 = 18.
7. How many more do you need to add to 21 to make 30?
9
Subtract 21 from 30: 30 − 21 = 9.
8. How many more do you need to add to 7 to make 100?
93
Subtract 7 from 100: 100 − 7 = 93.
9. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
10. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
11. How many more do you need to add to 91 to make 100?
9
Subtract 91 from 100: 100 − 91 = 9.
12. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.

12 questions · Seed 104734 · 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 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 14 to make 50?
14 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 5 to make 20?
5 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 18 to make 30?
18 · 30 · Complements to 10, 20 & 100
5. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 82 to make 100?
82 · 100 · Complements to 10, 20 & 100
7. How many more do you need to add to 21 to make 30?
21 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 7 to make 100?
7 · 100 · Complements to 10, 20 & 100
9. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
10. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
11. How many more do you need to add to 91 to make 100?
91 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100

12 questions · Seed 104734 · 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 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
2. How many more do you need to add to 14 to make 50?
36
Subtract 14 from 50: 50 − 14 = 36.
3. How many more do you need to add to 5 to make 20?
15
Subtract 5 from 20: 20 − 5 = 15.
4. How many more do you need to add to 18 to make 30?
12
Subtract 18 from 30: 30 − 18 = 12.
5. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
6. How many more do you need to add to 82 to make 100?
18
Subtract 82 from 100: 100 − 82 = 18.
7. How many more do you need to add to 21 to make 30?
9
Subtract 21 from 30: 30 − 21 = 9.
8. How many more do you need to add to 7 to make 100?
93
Subtract 7 from 100: 100 − 7 = 93.
9. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
10. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
11. How many more do you need to add to 91 to make 100?
9
Subtract 91 from 100: 100 − 91 = 9.
12. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.

12 questions · Seed 104734 · Age guidance, not curriculum certification