Back to worksheetsReasoningAges 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.
Worksheet StudioPractice pack · Ages 7-9
Missing sequence terms
Take your time. Show your thinking.
1. Find the missing number in the sequence: 3, 13, ____, 33, 43.
2. Find the missing number in the sequence: 12, 21, ____, 39, 48.
3. Find the missing number in the sequence: 17, 26, ____, 44, 53.
4. Find the missing number in the sequence: 2, 6, ____, 14, 18.
5. Find the missing number in the sequence: 8, 18, ____, 38, 48.
6. Find the missing number in the sequence: 3, 11, ____, 27, 35.
7. Find the missing number in the sequence: 12, 16, ____, 24, 28.
8. Find the missing number in the sequence: 14, 23, ____, 41, 50.
9. Find the missing number in the sequence: 9, 16, ____, 30, 37.
10. Find the missing number in the sequence: 10, 18, ____, 34, 42.
11. Find the missing number in the sequence: 19, 22, ____, 28, 31.
12. Find the missing number in the sequence: 5, 11, ____, 23, 29.
12 questions · Seed 104747 · 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: 3, 13, ____, 33, 43.
23The sequence increases by 10 each step: 13 + 10 = 23.
2. Find the missing number in the sequence: 12, 21, ____, 39, 48.
30The sequence increases by 9 each step: 21 + 9 = 30.
3. Find the missing number in the sequence: 17, 26, ____, 44, 53.
35The sequence increases by 9 each step: 26 + 9 = 35.
4. Find the missing number in the sequence: 2, 6, ____, 14, 18.
10The sequence increases by 4 each step: 6 + 4 = 10.
5. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28The sequence increases by 10 each step: 18 + 10 = 28.
6. Find the missing number in the sequence: 3, 11, ____, 27, 35.
19The sequence increases by 8 each step: 11 + 8 = 19.
7. Find the missing number in the sequence: 12, 16, ____, 24, 28.
20The sequence increases by 4 each step: 16 + 4 = 20.
8. Find the missing number in the sequence: 14, 23, ____, 41, 50.
32The sequence increases by 9 each step: 23 + 9 = 32.
9. Find the missing number in the sequence: 9, 16, ____, 30, 37.
23The sequence increases by 7 each step: 16 + 7 = 23.
10. Find the missing number in the sequence: 10, 18, ____, 34, 42.
26The sequence increases by 8 each step: 18 + 8 = 26.
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: 5, 11, ____, 23, 29.
17The sequence increases by 6 each step: 11 + 6 = 17.
12 questions · Seed 104747 · 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: 3, 13, ____, 33, 43.
2. Find the missing number in the sequence: 12, 21, ____, 39, 48.
3. Find the missing number in the sequence: 17, 26, ____, 44, 53.
4. Find the missing number in the sequence: 2, 6, ____, 14, 18.
5. Find the missing number in the sequence: 8, 18, ____, 38, 48.
6. Find the missing number in the sequence: 3, 11, ____, 27, 35.
7. Find the missing number in the sequence: 12, 16, ____, 24, 28.
8. Find the missing number in the sequence: 14, 23, ____, 41, 50.
9. Find the missing number in the sequence: 9, 16, ____, 30, 37.
10. Find the missing number in the sequence: 10, 18, ____, 34, 42.
11. Find the missing number in the sequence: 19, 22, ____, 28, 31.
12. Find the missing number in the sequence: 5, 11, ____, 23, 29.
12 questions · Seed 104747 · 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: 3, 13, ____, 33, 43.
23The sequence increases by 10 each step: 13 + 10 = 23.
2. Find the missing number in the sequence: 12, 21, ____, 39, 48.
30The sequence increases by 9 each step: 21 + 9 = 30.
3. Find the missing number in the sequence: 17, 26, ____, 44, 53.
35The sequence increases by 9 each step: 26 + 9 = 35.
4. Find the missing number in the sequence: 2, 6, ____, 14, 18.
10The sequence increases by 4 each step: 6 + 4 = 10.
5. Find the missing number in the sequence: 8, 18, ____, 38, 48.
28The sequence increases by 10 each step: 18 + 10 = 28.
6. Find the missing number in the sequence: 3, 11, ____, 27, 35.
19The sequence increases by 8 each step: 11 + 8 = 19.
7. Find the missing number in the sequence: 12, 16, ____, 24, 28.
20The sequence increases by 4 each step: 16 + 4 = 20.
8. Find the missing number in the sequence: 14, 23, ____, 41, 50.
32The sequence increases by 9 each step: 23 + 9 = 32.
9. Find the missing number in the sequence: 9, 16, ____, 30, 37.
23The sequence increases by 7 each step: 16 + 7 = 23.
10. Find the missing number in the sequence: 10, 18, ____, 34, 42.
26The sequence increases by 8 each step: 18 + 8 = 26.
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: 5, 11, ____, 23, 29.
17The sequence increases by 6 each step: 11 + 6 = 17.
12 questions · Seed 104747 · Age guidance, not curriculum certification