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.

Choose “Save as PDF” to keep a copy. Use your browser’s paper setting for A4 or Letter.

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 45 to make 100?
45 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 15 to make 50?
15 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 17 to make 50?
17 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 26 to make 30?
26 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 45 to make 50?
45 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 56 to make 100?
56 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 14 to make 100?
14 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 1 to make 50?
1 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 83 to make 100?
83 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 30?
6 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104743 · 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 45 to make 100?
55
Subtract 45 from 100: 100 − 45 = 55.
3. How many more do you need to add to 15 to make 50?
35
Subtract 15 from 50: 50 − 15 = 35.
4. How many more do you need to add to 17 to make 50?
33
Subtract 17 from 50: 50 − 17 = 33.
5. How many more do you need to add to 26 to make 30?
4
Subtract 26 from 30: 30 − 26 = 4.
6. How many more do you need to add to 45 to make 50?
5
Subtract 45 from 50: 50 − 45 = 5.
7. How many more do you need to add to 56 to make 100?
44
Subtract 56 from 100: 100 − 56 = 44.
8. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
9. How many more do you need to add to 14 to make 100?
86
Subtract 14 from 100: 100 − 14 = 86.
10. How many more do you need to add to 1 to make 50?
49
Subtract 1 from 50: 50 − 1 = 49.
11. How many more do you need to add to 83 to make 100?
17
Subtract 83 from 100: 100 − 83 = 17.
12. How many more do you need to add to 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.

12 questions · Seed 104743 · 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 45 to make 100?
45 · 100 · Complements to 10, 20 & 100
3. How many more do you need to add to 15 to make 50?
15 · 50 · Complements to 10, 20 & 100
4. How many more do you need to add to 17 to make 50?
17 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 26 to make 30?
26 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 45 to make 50?
45 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 56 to make 100?
56 · 100 · Complements to 10, 20 & 100
8. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
9. How many more do you need to add to 14 to make 100?
14 · 100 · Complements to 10, 20 & 100
10. How many more do you need to add to 1 to make 50?
1 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 83 to make 100?
83 · 100 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 30?
6 · 30 · Complements to 10, 20 & 100

12 questions · Seed 104743 · 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 45 to make 100?
55
Subtract 45 from 100: 100 − 45 = 55.
3. How many more do you need to add to 15 to make 50?
35
Subtract 15 from 50: 50 − 15 = 35.
4. How many more do you need to add to 17 to make 50?
33
Subtract 17 from 50: 50 − 17 = 33.
5. How many more do you need to add to 26 to make 30?
4
Subtract 26 from 30: 30 − 26 = 4.
6. How many more do you need to add to 45 to make 50?
5
Subtract 45 from 50: 50 − 45 = 5.
7. How many more do you need to add to 56 to make 100?
44
Subtract 56 from 100: 100 − 56 = 44.
8. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.
9. How many more do you need to add to 14 to make 100?
86
Subtract 14 from 100: 100 − 14 = 86.
10. How many more do you need to add to 1 to make 50?
49
Subtract 1 from 50: 50 − 1 = 49.
11. How many more do you need to add to 83 to make 100?
17
Subtract 83 from 100: 100 − 83 = 17.
12. How many more do you need to add to 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.

12 questions · Seed 104743 · Age guidance, not curriculum certification