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 14 to make 30?
14 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 31 to make 50?
31 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 38 to make 50?
38 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 74 to make 100?
74 · 100 · Complements to 10, 20 & 100
5. How many more do you need to add to 7 to make 30?
7 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 22 to make 30?
22 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 14 to make 50?
14 · 50 · Complements to 10, 20 & 100
10. How many more do you need to add to 15 to make 50?
15 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 13 to make 30?
13 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 8 to make 20?
8 · 20 · Complements to 10, 20 & 100

12 questions · Seed 44 · 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 14 to make 30?
16
Subtract 14 from 30: 30 − 14 = 16.
2. How many more do you need to add to 31 to make 50?
19
Subtract 31 from 50: 50 − 31 = 19.
3. How many more do you need to add to 38 to make 50?
12
Subtract 38 from 50: 50 − 38 = 12.
4. How many more do you need to add to 74 to make 100?
26
Subtract 74 from 100: 100 − 74 = 26.
5. How many more do you need to add to 7 to make 30?
23
Subtract 7 from 30: 30 − 7 = 23.
6. How many more do you need to add to 22 to make 30?
8
Subtract 22 from 30: 30 − 22 = 8.
7. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
8. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
9. How many more do you need to add to 14 to make 50?
36
Subtract 14 from 50: 50 − 14 = 36.
10. How many more do you need to add to 15 to make 50?
35
Subtract 15 from 50: 50 − 15 = 35.
11. How many more do you need to add to 13 to make 30?
17
Subtract 13 from 30: 30 − 13 = 17.
12. How many more do you need to add to 8 to make 20?
12
Subtract 8 from 20: 20 − 8 = 12.

12 questions · Seed 44 · 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 14 to make 30?
14 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 31 to make 50?
31 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 38 to make 50?
38 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 74 to make 100?
74 · 100 · Complements to 10, 20 & 100
5. How many more do you need to add to 7 to make 30?
7 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 22 to make 30?
22 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 14 to make 20?
14 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 14 to make 50?
14 · 50 · Complements to 10, 20 & 100
10. How many more do you need to add to 15 to make 50?
15 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 13 to make 30?
13 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 8 to make 20?
8 · 20 · Complements to 10, 20 & 100

12 questions · Seed 44 · 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 14 to make 30?
16
Subtract 14 from 30: 30 − 14 = 16.
2. How many more do you need to add to 31 to make 50?
19
Subtract 31 from 50: 50 − 31 = 19.
3. How many more do you need to add to 38 to make 50?
12
Subtract 38 from 50: 50 − 38 = 12.
4. How many more do you need to add to 74 to make 100?
26
Subtract 74 from 100: 100 − 74 = 26.
5. How many more do you need to add to 7 to make 30?
23
Subtract 7 from 30: 30 − 7 = 23.
6. How many more do you need to add to 22 to make 30?
8
Subtract 22 from 30: 30 − 22 = 8.
7. How many more do you need to add to 14 to make 20?
6
Subtract 14 from 20: 20 − 14 = 6.
8. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
9. How many more do you need to add to 14 to make 50?
36
Subtract 14 from 50: 50 − 14 = 36.
10. How many more do you need to add to 15 to make 50?
35
Subtract 15 from 50: 50 − 15 = 35.
11. How many more do you need to add to 13 to make 30?
17
Subtract 13 from 30: 30 − 13 = 17.
12. How many more do you need to add to 8 to make 20?
12
Subtract 8 from 20: 20 − 8 = 12.

12 questions · Seed 44 · Age guidance, not curriculum certification