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 6 to make 20?
6 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 5 to make 20?
5 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 8 to make 30?
8 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 2 to make 20?
2 · 20 · Complements to 10, 20 & 100
7. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 13 to make 30?
13 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 10 to make 30?
10 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 26 to make 30?
26 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100
12. How many more do you need to add to 77 to make 100?
77 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104775 · 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 20?
14
Subtract 6 from 20: 20 − 6 = 14.
2. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
3. How many more do you need to add to 5 to make 20?
15
Subtract 5 from 20: 20 − 5 = 15.
4. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.
5. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
6. How many more do you need to add to 2 to make 20?
18
Subtract 2 from 20: 20 − 2 = 18.
7. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
8. How many more do you need to add to 13 to make 30?
17
Subtract 13 from 30: 30 − 13 = 17.
9. How many more do you need to add to 10 to make 30?
20
Subtract 10 from 30: 30 − 10 = 20.
10. How many more do you need to add to 26 to make 30?
4
Subtract 26 from 30: 30 − 26 = 4.
11. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.
12. How many more do you need to add to 77 to make 100?
23
Subtract 77 from 100: 100 − 77 = 23.

12 questions · Seed 104775 · 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 20?
6 · 20 · Complements to 10, 20 & 100
2. How many more do you need to add to 23 to make 30?
23 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 5 to make 20?
5 · 20 · Complements to 10, 20 & 100
4. How many more do you need to add to 3 to make 20?
3 · 20 · Complements to 10, 20 & 100
5. How many more do you need to add to 8 to make 30?
8 · 30 · Complements to 10, 20 & 100
6. How many more do you need to add to 2 to make 20?
2 · 20 · Complements to 10, 20 & 100
7. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
8. How many more do you need to add to 13 to make 30?
13 · 30 · Complements to 10, 20 & 100
9. How many more do you need to add to 10 to make 30?
10 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 26 to make 30?
26 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 16 to make 20?
16 · 20 · Complements to 10, 20 & 100
12. How many more do you need to add to 77 to make 100?
77 · 100 · Complements to 10, 20 & 100

12 questions · Seed 104775 · 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 20?
14
Subtract 6 from 20: 20 − 6 = 14.
2. How many more do you need to add to 23 to make 30?
7
Subtract 23 from 30: 30 − 23 = 7.
3. How many more do you need to add to 5 to make 20?
15
Subtract 5 from 20: 20 − 5 = 15.
4. How many more do you need to add to 3 to make 20?
17
Subtract 3 from 20: 20 − 3 = 17.
5. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
6. How many more do you need to add to 2 to make 20?
18
Subtract 2 from 20: 20 − 2 = 18.
7. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
8. How many more do you need to add to 13 to make 30?
17
Subtract 13 from 30: 30 − 13 = 17.
9. How many more do you need to add to 10 to make 30?
20
Subtract 10 from 30: 30 − 10 = 20.
10. How many more do you need to add to 26 to make 30?
4
Subtract 26 from 30: 30 − 26 = 4.
11. How many more do you need to add to 16 to make 20?
4
Subtract 16 from 20: 20 − 16 = 4.
12. How many more do you need to add to 77 to make 100?
23
Subtract 77 from 100: 100 − 77 = 23.

12 questions · Seed 104775 · Age guidance, not curriculum certification