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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: 15, 18, ____, 24, 27.
2. Find the missing number in the sequence: 11, 21, ____, 41, 51.
3. Find the missing number in the sequence: 17, 23, ____, 35, 41.
4. Find the missing number in the sequence: 13, 23, ____, 43, 53.
5. Find the missing number in the sequence: 5, 14, ____, 32, 41.
6. Find the missing number in the sequence: 4, 7, ____, 13, 16.
7. Find the missing number in the sequence: 14, 21, ____, 35, 42.
8. Find the missing number in the sequence: 18, 21, ____, 27, 30.
9. Find the missing number in the sequence: 11, 14, ____, 20, 23.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
11. Find the missing number in the sequence: 19, 28, ____, 46, 55.
12. Find the missing number in the sequence: 12, 19, ____, 33, 40.
12 questions · Seed 92 · 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: 15, 18, ____, 24, 27.
21The sequence increases by 3 each step: 18 + 3 = 21.
2. Find the missing number in the sequence: 11, 21, ____, 41, 51.
31The sequence increases by 10 each step: 21 + 10 = 31.
3. Find the missing number in the sequence: 17, 23, ____, 35, 41.
29The sequence increases by 6 each step: 23 + 6 = 29.
4. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33The sequence increases by 10 each step: 23 + 10 = 33.
5. Find the missing number in the sequence: 5, 14, ____, 32, 41.
23The sequence increases by 9 each step: 14 + 9 = 23.
6. Find the missing number in the sequence: 4, 7, ____, 13, 16.
10The sequence increases by 3 each step: 7 + 3 = 10.
7. Find the missing number in the sequence: 14, 21, ____, 35, 42.
28The sequence increases by 7 each step: 21 + 7 = 28.
8. Find the missing number in the sequence: 18, 21, ____, 27, 30.
24The sequence increases by 3 each step: 21 + 3 = 24.
9. Find the missing number in the sequence: 11, 14, ____, 20, 23.
17The sequence increases by 3 each step: 14 + 3 = 17.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17The sequence increases by 6 each step: 11 + 6 = 17.
11. Find the missing number in the sequence: 19, 28, ____, 46, 55.
37The sequence increases by 9 each step: 28 + 9 = 37.
12. Find the missing number in the sequence: 12, 19, ____, 33, 40.
26The sequence increases by 7 each step: 19 + 7 = 26.
12 questions · Seed 92 · 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: 15, 18, ____, 24, 27.
2. Find the missing number in the sequence: 11, 21, ____, 41, 51.
3. Find the missing number in the sequence: 17, 23, ____, 35, 41.
4. Find the missing number in the sequence: 13, 23, ____, 43, 53.
5. Find the missing number in the sequence: 5, 14, ____, 32, 41.
6. Find the missing number in the sequence: 4, 7, ____, 13, 16.
7. Find the missing number in the sequence: 14, 21, ____, 35, 42.
8. Find the missing number in the sequence: 18, 21, ____, 27, 30.
9. Find the missing number in the sequence: 11, 14, ____, 20, 23.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
11. Find the missing number in the sequence: 19, 28, ____, 46, 55.
12. Find the missing number in the sequence: 12, 19, ____, 33, 40.
12 questions · Seed 92 · 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: 15, 18, ____, 24, 27.
21The sequence increases by 3 each step: 18 + 3 = 21.
2. Find the missing number in the sequence: 11, 21, ____, 41, 51.
31The sequence increases by 10 each step: 21 + 10 = 31.
3. Find the missing number in the sequence: 17, 23, ____, 35, 41.
29The sequence increases by 6 each step: 23 + 6 = 29.
4. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33The sequence increases by 10 each step: 23 + 10 = 33.
5. Find the missing number in the sequence: 5, 14, ____, 32, 41.
23The sequence increases by 9 each step: 14 + 9 = 23.
6. Find the missing number in the sequence: 4, 7, ____, 13, 16.
10The sequence increases by 3 each step: 7 + 3 = 10.
7. Find the missing number in the sequence: 14, 21, ____, 35, 42.
28The sequence increases by 7 each step: 21 + 7 = 28.
8. Find the missing number in the sequence: 18, 21, ____, 27, 30.
24The sequence increases by 3 each step: 21 + 3 = 24.
9. Find the missing number in the sequence: 11, 14, ____, 20, 23.
17The sequence increases by 3 each step: 14 + 3 = 17.
10. Find the missing number in the sequence: 5, 11, ____, 23, 29.
17The sequence increases by 6 each step: 11 + 6 = 17.
11. Find the missing number in the sequence: 19, 28, ____, 46, 55.
37The sequence increases by 9 each step: 28 + 9 = 37.
12. Find the missing number in the sequence: 12, 19, ____, 33, 40.
26The sequence increases by 7 each step: 19 + 7 = 26.
12 questions · Seed 92 · Age guidance, not curriculum certification