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 6 to make 30?
6 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 43 to make 50?
43 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 24 to make 30?
24 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 18 to make 50?
18 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 38 to make 50?
38 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 7 to make 30?
7 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104764 · 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 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.
2. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
3. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
4. How many more do you need to add to 43 to make 50?
7
Subtract 43 from 50: 50 − 43 = 7.
5. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
6. How many more do you need to add to 24 to make 30?
6
Subtract 24 from 30: 30 − 24 = 6.
7. How many more do you need to add to 18 to make 50?
32
Subtract 18 from 50: 50 − 18 = 32.
8. How many more do you need to add to 38 to make 50?
12
Subtract 38 from 50: 50 − 38 = 12.
9. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
10. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
11. How many more do you need to add to 7 to make 30?
23
Subtract 7 from 30: 30 − 7 = 23.
12. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.

12 questions · Seed 104764 · 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 6 to make 30?
6 · 30 · Complements to 10, 20 & 100
2. How many more do you need to add to 28 to make 50?
28 · 50 · Complements to 10, 20 & 100
3. How many more do you need to add to 18 to make 20?
18 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 43 to make 50?
43 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 24 to make 30?
24 · 30 · Complements to 10, 20 & 100
7. How many more do you need to add to 18 to make 50?
18 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 38 to make 50?
38 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 32 to make 50?
32 · 50 · Complements to 10, 20 & 100
11. How many more do you need to add to 7 to make 30?
7 · 30 · Complements to 10, 20 & 100
12. How many more do you need to add to 6 to make 20?
6 · 20 · Complements to 10, 20 & 100

12 questions · Seed 104764 · 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 6 to make 30?
24
Subtract 6 from 30: 30 − 6 = 24.
2. How many more do you need to add to 28 to make 50?
22
Subtract 28 from 50: 50 − 28 = 22.
3. How many more do you need to add to 18 to make 20?
2
Subtract 18 from 20: 20 − 18 = 2.
4. How many more do you need to add to 43 to make 50?
7
Subtract 43 from 50: 50 − 43 = 7.
5. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
6. How many more do you need to add to 24 to make 30?
6
Subtract 24 from 30: 30 − 24 = 6.
7. How many more do you need to add to 18 to make 50?
32
Subtract 18 from 50: 50 − 18 = 32.
8. How many more do you need to add to 38 to make 50?
12
Subtract 38 from 50: 50 − 38 = 12.
9. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
10. How many more do you need to add to 32 to make 50?
18
Subtract 32 from 50: 50 − 32 = 18.
11. How many more do you need to add to 7 to make 30?
23
Subtract 7 from 30: 30 − 7 = 23.
12. How many more do you need to add to 6 to make 20?
14
Subtract 6 from 20: 20 − 6 = 14.

12 questions · Seed 104764 · Age guidance, not curriculum certification