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 26 to make 30?
26 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
4. How many more do you need to add to 34 to make 50?
34 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 11 to make 100?
11 · 100 · Complements to 10, 20 & 100
6. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 35 to make 50?
35 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 18 to make 50?
18 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 1 to make 30?
1 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 8 to make 30?
8 · 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 104773 · 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 26 to make 30?
4
Subtract 26 from 30: 30 − 26 = 4.
3. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
4. How many more do you need to add to 34 to make 50?
16
Subtract 34 from 50: 50 − 34 = 16.
5. How many more do you need to add to 11 to make 100?
89
Subtract 11 from 100: 100 − 11 = 89.
6. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
7. How many more do you need to add to 35 to make 50?
15
Subtract 35 from 50: 50 − 35 = 15.
8. How many more do you need to add to 18 to make 50?
32
Subtract 18 from 50: 50 − 18 = 32.
9. How many more do you need to add to 1 to make 30?
29
Subtract 1 from 30: 30 − 1 = 29.
10. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
11. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
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 104773 · 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 26 to make 30?
26 · 30 · Complements to 10, 20 & 100
3. How many more do you need to add to 19 to make 30?
19 · 30 · Complements to 10, 20 & 100
4. How many more do you need to add to 34 to make 50?
34 · 50 · Complements to 10, 20 & 100
5. How many more do you need to add to 11 to make 100?
11 · 100 · Complements to 10, 20 & 100
6. How many more do you need to add to 24 to make 50?
24 · 50 · Complements to 10, 20 & 100
7. How many more do you need to add to 35 to make 50?
35 · 50 · Complements to 10, 20 & 100
8. How many more do you need to add to 18 to make 50?
18 · 50 · Complements to 10, 20 & 100
9. How many more do you need to add to 1 to make 30?
1 · 30 · Complements to 10, 20 & 100
10. How many more do you need to add to 25 to make 30?
25 · 30 · Complements to 10, 20 & 100
11. How many more do you need to add to 8 to make 30?
8 · 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 104773 · 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 26 to make 30?
4
Subtract 26 from 30: 30 − 26 = 4.
3. How many more do you need to add to 19 to make 30?
11
Subtract 19 from 30: 30 − 19 = 11.
4. How many more do you need to add to 34 to make 50?
16
Subtract 34 from 50: 50 − 34 = 16.
5. How many more do you need to add to 11 to make 100?
89
Subtract 11 from 100: 100 − 11 = 89.
6. How many more do you need to add to 24 to make 50?
26
Subtract 24 from 50: 50 − 24 = 26.
7. How many more do you need to add to 35 to make 50?
15
Subtract 35 from 50: 50 − 35 = 15.
8. How many more do you need to add to 18 to make 50?
32
Subtract 18 from 50: 50 − 18 = 32.
9. How many more do you need to add to 1 to make 30?
29
Subtract 1 from 30: 30 − 1 = 29.
10. How many more do you need to add to 25 to make 30?
5
Subtract 25 from 30: 30 − 25 = 5.
11. How many more do you need to add to 8 to make 30?
22
Subtract 8 from 30: 30 − 8 = 22.
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 104773 · Age guidance, not curriculum certification