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 94 to make 100?
94 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 97 to make 100?
97 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 18 to make 100?
18 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 4 to make 30?
4 · 30 · Complements to 10, 20 & 100
5. How many more do you need to add to 28 to make 30?
28 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 18 to make 30?
18 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 13 to make 20?
13 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 11 to make 30?
11 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 78 to make 100?
78 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 91 to make 100?
91 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 16 to make 30?
16 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 1 to make 20?
1 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104749 · 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 94 to make 100?
6
Subtract 94 from 100: 100 − 94 = 6.
2. How many more do you need to add to 97 to make 100?
3
Subtract 97 from 100: 100 − 97 = 3.
3. How many more do you need to add to 18 to make 100?
82
Subtract 18 from 100: 100 − 18 = 82.
4. How many more do you need to add to 4 to make 30?
26
Subtract 4 from 30: 30 − 4 = 26.
5. How many more do you need to add to 28 to make 30?
2
Subtract 28 from 30: 30 − 28 = 2.
6. How many more do you need to add to 18 to make 30?
12
Subtract 18 from 30: 30 − 18 = 12.
7. How many more do you need to add to 13 to make 20?
7
Subtract 13 from 20: 20 − 13 = 7.
8. How many more do you need to add to 11 to make 30?
19
Subtract 11 from 30: 30 − 11 = 19.
9. How many more do you need to add to 78 to make 100?
22
Subtract 78 from 100: 100 − 78 = 22.
10. How many more do you need to add to 91 to make 100?
9
Subtract 91 from 100: 100 − 91 = 9.
11. How many more do you need to add to 16 to make 30?
14
Subtract 16 from 30: 30 − 16 = 14.
12. How many more do you need to add to 1 to make 20?
19
Subtract 1 from 20: 20 − 1 = 19.

12 questions · Seed 104749 · 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 94 to make 100?
94 · 100 · Complements to 10, 20 & 100
2. How many more do you need to add to 97 to make 100?
97 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 18 to make 100?
18 · 100 · Complements to 10, 20 & 100
4. How many more do you need to add to 4 to make 30?
4 · 30 · Complements to 10, 20 & 100
5. How many more do you need to add to 28 to make 30?
28 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 18 to make 30?
18 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 13 to make 20?
13 · 20 · Complements to 10, 20 & 100
8. How many more do you need to add to 11 to make 30?
11 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 78 to make 100?
78 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 91 to make 100?
91 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 16 to make 30?
16 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 1 to make 20?
1 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104749 · 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 94 to make 100?
6
Subtract 94 from 100: 100 − 94 = 6.
2. How many more do you need to add to 97 to make 100?
3
Subtract 97 from 100: 100 − 97 = 3.
3. How many more do you need to add to 18 to make 100?
82
Subtract 18 from 100: 100 − 18 = 82.
4. How many more do you need to add to 4 to make 30?
26
Subtract 4 from 30: 30 − 4 = 26.
5. How many more do you need to add to 28 to make 30?
2
Subtract 28 from 30: 30 − 28 = 2.
6. How many more do you need to add to 18 to make 30?
12
Subtract 18 from 30: 30 − 18 = 12.
7. How many more do you need to add to 13 to make 20?
7
Subtract 13 from 20: 20 − 13 = 7.
8. How many more do you need to add to 11 to make 30?
19
Subtract 11 from 30: 30 − 11 = 19.
9. How many more do you need to add to 78 to make 100?
22
Subtract 78 from 100: 100 − 78 = 22.
10. How many more do you need to add to 91 to make 100?
9
Subtract 91 from 100: 100 − 91 = 9.
11. How many more do you need to add to 16 to make 30?
14
Subtract 16 from 30: 30 − 16 = 14.
12. How many more do you need to add to 1 to make 20?
19
Subtract 1 from 20: 20 − 1 = 19.

12 questions · Seed 104749 · Age guidance, not curriculum certification