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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.
Worksheet StudioPractice pack · Ages 7-9
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 20, 29, ____, 47, 56.
2. Find the missing number in the sequence: 7, 13, ____, 25, 31.
3. Find the missing number in the sequence: 15, 23, ____, 39, 47.
4. Find the missing number in the sequence: 9, 15, ____, 27, 33.
5. Find the missing number in the sequence: 5, 13, ____, 29, 37.
6. Find the missing number in the sequence: 2, 12, ____, 32, 42.
7. Find the missing number in the sequence: 8, 18, ____, 38, 48.
8. Find the missing number in the sequence: 11, 21, ____, 41, 51.
9. Find the missing number in the sequence: 1, 4, ____, 10, 13.
10. Find the missing number in the sequence: 6, 9, ____, 15, 18.
11. Find the missing number in the sequence: 10, 14, ____, 22, 26.
12. Find the missing number in the sequence: 6, 13, ____, 27, 34.
12 questions · Seed 104 · Age guidance, not curriculum certification
View the answer key
Worksheet StudioAnswer key · Ages 7-9
Missing sequence terms
Answers and reasoning. Review before teaching.
1. Find the missing number in the sequence: 20, 29, ____, 47, 56.
38The sequence increases by 9 each step: 29 + 9 = 38.
2. Find the missing number in the sequence: 7, 13, ____, 25, 31.
19The sequence increases by 6 each step: 13 + 6 = 19.
3. Find the missing number in the sequence: 15, 23, ____, 39, 47.
31The sequence increases by 8 each step: 23 + 8 = 31.
4. Find the missing number in the sequence: 9, 15, ____, 27, 33.
21The sequence increases by 6 each step: 15 + 6 = 21.
5. Find the missing number in the sequence: 5, 13, ____, 29, 37.
21The sequence increases by 8 each step: 13 + 8 = 21.
6. Find the missing number in the sequence: 2, 12, ____, 32, 42.
22The sequence increases by 10 each step: 12 + 10 = 22.
7. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28The sequence increases by 10 each step: 18 + 10 = 28.
8. Find the missing number in the sequence: 11, 21, ____, 41, 51.
31The sequence increases by 10 each step: 21 + 10 = 31.
9. Find the missing number in the sequence: 1, 4, ____, 10, 13.
7The sequence increases by 3 each step: 4 + 3 = 7.
10. Find the missing number in the sequence: 6, 9, ____, 15, 18.
12The sequence increases by 3 each step: 9 + 3 = 12.
11. Find the missing number in the sequence: 10, 14, ____, 22, 26.
18The sequence increases by 4 each step: 14 + 4 = 18.
12. Find the missing number in the sequence: 6, 13, ____, 27, 34.
20The sequence increases by 7 each step: 13 + 7 = 20.
12 questions · Seed 104 · Age guidance, not curriculum certification
Worksheet StudioPractice pack · Ages 7-9
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 20, 29, ____, 47, 56.
2. Find the missing number in the sequence: 7, 13, ____, 25, 31.
3. Find the missing number in the sequence: 15, 23, ____, 39, 47.
4. Find the missing number in the sequence: 9, 15, ____, 27, 33.
5. Find the missing number in the sequence: 5, 13, ____, 29, 37.
6. Find the missing number in the sequence: 2, 12, ____, 32, 42.
7. Find the missing number in the sequence: 8, 18, ____, 38, 48.
8. Find the missing number in the sequence: 11, 21, ____, 41, 51.
9. Find the missing number in the sequence: 1, 4, ____, 10, 13.
10. Find the missing number in the sequence: 6, 9, ____, 15, 18.
11. Find the missing number in the sequence: 10, 14, ____, 22, 26.
12. Find the missing number in the sequence: 6, 13, ____, 27, 34.
12 questions · Seed 104 · Age guidance, not curriculum certification
Worksheet StudioAnswer key · Ages 7-9
Missing sequence terms
Answers and reasoning. Review before teaching.
1. Find the missing number in the sequence: 20, 29, ____, 47, 56.
38The sequence increases by 9 each step: 29 + 9 = 38.
2. Find the missing number in the sequence: 7, 13, ____, 25, 31.
19The sequence increases by 6 each step: 13 + 6 = 19.
3. Find the missing number in the sequence: 15, 23, ____, 39, 47.
31The sequence increases by 8 each step: 23 + 8 = 31.
4. Find the missing number in the sequence: 9, 15, ____, 27, 33.
21The sequence increases by 6 each step: 15 + 6 = 21.
5. Find the missing number in the sequence: 5, 13, ____, 29, 37.
21The sequence increases by 8 each step: 13 + 8 = 21.
6. Find the missing number in the sequence: 2, 12, ____, 32, 42.
22The sequence increases by 10 each step: 12 + 10 = 22.
7. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28The sequence increases by 10 each step: 18 + 10 = 28.
8. Find the missing number in the sequence: 11, 21, ____, 41, 51.
31The sequence increases by 10 each step: 21 + 10 = 31.
9. Find the missing number in the sequence: 1, 4, ____, 10, 13.
7The sequence increases by 3 each step: 4 + 3 = 7.
10. Find the missing number in the sequence: 6, 9, ____, 15, 18.
12The sequence increases by 3 each step: 9 + 3 = 12.
11. Find the missing number in the sequence: 10, 14, ____, 22, 26.
18The sequence increases by 4 each step: 14 + 4 = 18.
12. Find the missing number in the sequence: 6, 13, ____, 27, 34.
20The sequence increases by 7 each step: 13 + 7 = 20.
12 questions · Seed 104 · Age guidance, not curriculum certification