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 20?
14 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 2 to make 30?
2 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 1 to make 20?
1 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 17 to make 20?
17 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100
7. How many more do you need to add to 6 to make 30?
6 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 27 to make 30?
27 · 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 5 to make 100?
5 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 63 to make 100?
63 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104757 · 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 20?
6
Subtract 14 from 20: 20 − 14 = 6.
2. How many more do you need to add to 2 to make 30?
28
Subtract 2 from 30: 30 − 2 = 28.
3. How many more do you need to add to 1 to make 20?
19
Subtract 1 from 20: 20 − 1 = 19.
4. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
5. How many more do you need to add to 17 to make 20?
3
Subtract 17 from 20: 20 − 17 = 3.
6. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.
7. How many more do you need to add to 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.
8. How many more do you need to add to 27 to make 30?
3
Subtract 27 from 30: 30 − 27 = 3.
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 5 to make 100?
95
Subtract 5 from 100: 100 − 5 = 95.
11. How many more do you need to add to 63 to make 100?
37
Subtract 63 from 100: 100 − 63 = 37.
12. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.

12 questions · Seed 104757 · 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 20?
14 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 2 to make 30?
2 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 1 to make 20?
1 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 17 to make 20?
17 · 20 · Complements to 10, 20 & 100
6. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100
7. How many more do you need to add to 6 to make 30?
6 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 27 to make 30?
27 · 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 5 to make 100?
5 · 100 · Complements to 10, 20 & 100
11. How many more do you need to add to 63 to make 100?
63 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104757 · 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 20?
6
Subtract 14 from 20: 20 − 14 = 6.
2. How many more do you need to add to 2 to make 30?
28
Subtract 2 from 30: 30 − 2 = 28.
3. How many more do you need to add to 1 to make 20?
19
Subtract 1 from 20: 20 − 1 = 19.
4. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
5. How many more do you need to add to 17 to make 20?
3
Subtract 17 from 20: 20 − 17 = 3.
6. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.
7. How many more do you need to add to 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.
8. How many more do you need to add to 27 to make 30?
3
Subtract 27 from 30: 30 − 27 = 3.
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 5 to make 100?
95
Subtract 5 from 100: 100 − 5 = 95.
11. How many more do you need to add to 63 to make 100?
37
Subtract 63 from 100: 100 − 63 = 37.
12. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.

12 questions · Seed 104757 · Age guidance, not curriculum certification