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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, 27, ____, 41, 48.
2. Find the missing number in the sequence: 20, 24, ____, 32, 36.
3. Find the missing number in the sequence: 13, 23, ____, 43, 53.
4. Find the missing number in the sequence: 11, 21, ____, 41, 51.
5. Find the missing number in the sequence: 6, 14, ____, 30, 38.
6. Find the missing number in the sequence: 2, 9, ____, 23, 30.
7. Find the missing number in the sequence: 17, 21, ____, 29, 33.
8. Find the missing number in the sequence: 18, 25, ____, 39, 46.
9. Find the missing number in the sequence: 3, 6, ____, 12, 15.
10. Find the missing number in the sequence: 19, 29, ____, 49, 59.
11. Find the missing number in the sequence: 19, 22, ____, 28, 31.
12. Find the missing number in the sequence: 19, 23, ____, 31, 35.
12 questions · Seed 105 · 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, 27, ____, 41, 48.
34The sequence increases by 7 each step: 27 + 7 = 34.
2. Find the missing number in the sequence: 20, 24, ____, 32, 36.
28The sequence increases by 4 each step: 24 + 4 = 28.
3. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33The sequence increases by 10 each step: 23 + 10 = 33.
4. Find the missing number in the sequence: 11, 21, ____, 41, 51.
31The sequence increases by 10 each step: 21 + 10 = 31.
5. Find the missing number in the sequence: 6, 14, ____, 30, 38.
22The sequence increases by 8 each step: 14 + 8 = 22.
6. Find the missing number in the sequence: 2, 9, ____, 23, 30.
16The sequence increases by 7 each step: 9 + 7 = 16.
7. Find the missing number in the sequence: 17, 21, ____, 29, 33.
25The sequence increases by 4 each step: 21 + 4 = 25.
8. Find the missing number in the sequence: 18, 25, ____, 39, 46.
32The sequence increases by 7 each step: 25 + 7 = 32.
9. Find the missing number in the sequence: 3, 6, ____, 12, 15.
9The sequence increases by 3 each step: 6 + 3 = 9.
10. Find the missing number in the sequence: 19, 29, ____, 49, 59.
39The sequence increases by 10 each step: 29 + 10 = 39.
11. Find the missing number in the sequence: 19, 22, ____, 28, 31.
25The sequence increases by 3 each step: 22 + 3 = 25.
12. Find the missing number in the sequence: 19, 23, ____, 31, 35.
27The sequence increases by 4 each step: 23 + 4 = 27.
12 questions · Seed 105 · 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, 27, ____, 41, 48.
2. Find the missing number in the sequence: 20, 24, ____, 32, 36.
3. Find the missing number in the sequence: 13, 23, ____, 43, 53.
4. Find the missing number in the sequence: 11, 21, ____, 41, 51.
5. Find the missing number in the sequence: 6, 14, ____, 30, 38.
6. Find the missing number in the sequence: 2, 9, ____, 23, 30.
7. Find the missing number in the sequence: 17, 21, ____, 29, 33.
8. Find the missing number in the sequence: 18, 25, ____, 39, 46.
9. Find the missing number in the sequence: 3, 6, ____, 12, 15.
10. Find the missing number in the sequence: 19, 29, ____, 49, 59.
11. Find the missing number in the sequence: 19, 22, ____, 28, 31.
12. Find the missing number in the sequence: 19, 23, ____, 31, 35.
12 questions · Seed 105 · 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, 27, ____, 41, 48.
34The sequence increases by 7 each step: 27 + 7 = 34.
2. Find the missing number in the sequence: 20, 24, ____, 32, 36.
28The sequence increases by 4 each step: 24 + 4 = 28.
3. Find the missing number in the sequence: 13, 23, ____, 43, 53.
33The sequence increases by 10 each step: 23 + 10 = 33.
4. Find the missing number in the sequence: 11, 21, ____, 41, 51.
31The sequence increases by 10 each step: 21 + 10 = 31.
5. Find the missing number in the sequence: 6, 14, ____, 30, 38.
22The sequence increases by 8 each step: 14 + 8 = 22.
6. Find the missing number in the sequence: 2, 9, ____, 23, 30.
16The sequence increases by 7 each step: 9 + 7 = 16.
7. Find the missing number in the sequence: 17, 21, ____, 29, 33.
25The sequence increases by 4 each step: 21 + 4 = 25.
8. Find the missing number in the sequence: 18, 25, ____, 39, 46.
32The sequence increases by 7 each step: 25 + 7 = 32.
9. Find the missing number in the sequence: 3, 6, ____, 12, 15.
9The sequence increases by 3 each step: 6 + 3 = 9.
10. Find the missing number in the sequence: 19, 29, ____, 49, 59.
39The sequence increases by 10 each step: 29 + 10 = 39.
11. Find the missing number in the sequence: 19, 22, ____, 28, 31.
25The sequence increases by 3 each step: 22 + 3 = 25.
12. Find the missing number in the sequence: 19, 23, ____, 31, 35.
27The sequence increases by 4 each step: 23 + 4 = 27.
12 questions · Seed 105 · Age guidance, not curriculum certification