ReasoningAges 7-9

Missing sequence terms

Use the constant step size between terms to find the missing middle number in a sequence. Review suitability for your learners before teaching.

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Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

12 questions · Seed 65 · Age guidance, not curriculum certification

View the answer key

Worksheet StudioAnswer key · Ages 7-9

Answers and reasoning. Review before teaching.

1. Find the missing number in the sequence: 3, 12, ____, 30, 39.
21
The sequence increases by 9 each step: 12 + 9 = 21.
2. Find the missing number in the sequence: 20, 29, ____, 47, 56.
38
The sequence increases by 9 each step: 29 + 9 = 38.
3. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33
The sequence increases by 10 each step: 23 + 10 = 33.
4. Find the missing number in the sequence: 19, 25, ____, 37, 43.
31
The sequence increases by 6 each step: 25 + 6 = 31.
5. Find the missing number in the sequence: 15, 23, ____, 39, 47.
31
The sequence increases by 8 each step: 23 + 8 = 31.
6. Find the missing number in the sequence: 5, 13, ____, 29, 37.
21
The sequence increases by 8 each step: 13 + 8 = 21.
7. Find the missing number in the sequence: 13, 22, ____, 40, 49.
31
The sequence increases by 9 each step: 22 + 9 = 31.
8. Find the missing number in the sequence: 15, 22, ____, 36, 43.
29
The sequence increases by 7 each step: 22 + 7 = 29.
9. Find the missing number in the sequence: 20, 30, ____, 50, 60.
40
The sequence increases by 10 each step: 30 + 10 = 40.
10. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28
The sequence increases by 10 each step: 18 + 10 = 28.
11. Find the missing number in the sequence: 12, 15, ____, 21, 24.
18
The sequence increases by 3 each step: 15 + 3 = 18.
12. Find the missing number in the sequence: 7, 15, ____, 31, 39.
23
The sequence increases by 8 each step: 15 + 8 = 23.

12 questions · Seed 65 · Age guidance, not curriculum certification

Worksheet StudioPractice pack · Ages 7-9

Take your time. Show your thinking.

12 questions · Seed 65 · Age guidance, not curriculum certification

Worksheet StudioAnswer key · Ages 7-9

Answers and reasoning. Review before teaching.

1. Find the missing number in the sequence: 3, 12, ____, 30, 39.
21
The sequence increases by 9 each step: 12 + 9 = 21.
2. Find the missing number in the sequence: 20, 29, ____, 47, 56.
38
The sequence increases by 9 each step: 29 + 9 = 38.
3. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33
The sequence increases by 10 each step: 23 + 10 = 33.
4. Find the missing number in the sequence: 19, 25, ____, 37, 43.
31
The sequence increases by 6 each step: 25 + 6 = 31.
5. Find the missing number in the sequence: 15, 23, ____, 39, 47.
31
The sequence increases by 8 each step: 23 + 8 = 31.
6. Find the missing number in the sequence: 5, 13, ____, 29, 37.
21
The sequence increases by 8 each step: 13 + 8 = 21.
7. Find the missing number in the sequence: 13, 22, ____, 40, 49.
31
The sequence increases by 9 each step: 22 + 9 = 31.
8. Find the missing number in the sequence: 15, 22, ____, 36, 43.
29
The sequence increases by 7 each step: 22 + 7 = 29.
9. Find the missing number in the sequence: 20, 30, ____, 50, 60.
40
The sequence increases by 10 each step: 30 + 10 = 40.
10. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28
The sequence increases by 10 each step: 18 + 10 = 28.
11. Find the missing number in the sequence: 12, 15, ____, 21, 24.
18
The sequence increases by 3 each step: 15 + 3 = 18.
12. Find the missing number in the sequence: 7, 15, ____, 31, 39.
23
The sequence increases by 8 each step: 15 + 8 = 23.

12 questions · Seed 65 · Age guidance, not curriculum certification