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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: 9, 12, ____, 18, 21.
2. Find the missing number in the sequence: 16, 24, ____, 40, 48.
3. Find the missing number in the sequence: 20, 26, ____, 38, 44.
4. Find the missing number in the sequence: 13, 19, ____, 31, 37.
5. Find the missing number in the sequence: 7, 11, ____, 19, 23.
6. Find the missing number in the sequence: 10, 14, ____, 22, 26.
7. Find the missing number in the sequence: 11, 20, ____, 38, 47.
8. Find the missing number in the sequence: 6, 9, ____, 15, 18.
9. Find the missing number in the sequence: 8, 18, ____, 38, 48.
10. Find the missing number in the sequence: 20, 23, ____, 29, 32.
11. Find the missing number in the sequence: 3, 11, ____, 27, 35.
12. Find the missing number in the sequence: 3, 10, ____, 24, 31.
12 questions · Seed 57 · 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: 9, 12, ____, 18, 21.
15The sequence increases by 3 each step: 12 + 3 = 15.
2. Find the missing number in the sequence: 16, 24, ____, 40, 48.
32The sequence increases by 8 each step: 24 + 8 = 32.
3. Find the missing number in the sequence: 20, 26, ____, 38, 44.
32The sequence increases by 6 each step: 26 + 6 = 32.
4. Find the missing number in the sequence: 13, 19, ____, 31, 37.
25The sequence increases by 6 each step: 19 + 6 = 25.
5. Find the missing number in the sequence: 7, 11, ____, 19, 23.
15The sequence increases by 4 each step: 11 + 4 = 15.
6. Find the missing number in the sequence: 10, 14, ____, 22, 26.
18The sequence increases by 4 each step: 14 + 4 = 18.
7. Find the missing number in the sequence: 11, 20, ____, 38, 47.
29The sequence increases by 9 each step: 20 + 9 = 29.
8. Find the missing number in the sequence: 6, 9, ____, 15, 18.
12The sequence increases by 3 each step: 9 + 3 = 12.
9. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28The sequence increases by 10 each step: 18 + 10 = 28.
10. Find the missing number in the sequence: 20, 23, ____, 29, 32.
26The sequence increases by 3 each step: 23 + 3 = 26.
11. Find the missing number in the sequence: 3, 11, ____, 27, 35.
19The sequence increases by 8 each step: 11 + 8 = 19.
12. Find the missing number in the sequence: 3, 10, ____, 24, 31.
17The sequence increases by 7 each step: 10 + 7 = 17.
12 questions · Seed 57 · 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: 9, 12, ____, 18, 21.
2. Find the missing number in the sequence: 16, 24, ____, 40, 48.
3. Find the missing number in the sequence: 20, 26, ____, 38, 44.
4. Find the missing number in the sequence: 13, 19, ____, 31, 37.
5. Find the missing number in the sequence: 7, 11, ____, 19, 23.
6. Find the missing number in the sequence: 10, 14, ____, 22, 26.
7. Find the missing number in the sequence: 11, 20, ____, 38, 47.
8. Find the missing number in the sequence: 6, 9, ____, 15, 18.
9. Find the missing number in the sequence: 8, 18, ____, 38, 48.
10. Find the missing number in the sequence: 20, 23, ____, 29, 32.
11. Find the missing number in the sequence: 3, 11, ____, 27, 35.
12. Find the missing number in the sequence: 3, 10, ____, 24, 31.
12 questions · Seed 57 · 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: 9, 12, ____, 18, 21.
15The sequence increases by 3 each step: 12 + 3 = 15.
2. Find the missing number in the sequence: 16, 24, ____, 40, 48.
32The sequence increases by 8 each step: 24 + 8 = 32.
3. Find the missing number in the sequence: 20, 26, ____, 38, 44.
32The sequence increases by 6 each step: 26 + 6 = 32.
4. Find the missing number in the sequence: 13, 19, ____, 31, 37.
25The sequence increases by 6 each step: 19 + 6 = 25.
5. Find the missing number in the sequence: 7, 11, ____, 19, 23.
15The sequence increases by 4 each step: 11 + 4 = 15.
6. Find the missing number in the sequence: 10, 14, ____, 22, 26.
18The sequence increases by 4 each step: 14 + 4 = 18.
7. Find the missing number in the sequence: 11, 20, ____, 38, 47.
29The sequence increases by 9 each step: 20 + 9 = 29.
8. Find the missing number in the sequence: 6, 9, ____, 15, 18.
12The sequence increases by 3 each step: 9 + 3 = 12.
9. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28The sequence increases by 10 each step: 18 + 10 = 28.
10. Find the missing number in the sequence: 20, 23, ____, 29, 32.
26The sequence increases by 3 each step: 23 + 3 = 26.
11. Find the missing number in the sequence: 3, 11, ____, 27, 35.
19The sequence increases by 8 each step: 11 + 8 = 19.
12. Find the missing number in the sequence: 3, 10, ____, 24, 31.
17The sequence increases by 7 each step: 10 + 7 = 17.
12 questions · Seed 57 · Age guidance, not curriculum certification