Number sequences worksheet for children with fun animal-themed math exercises.

To solve the missing numbers in the sequences, we need to identify the pattern or rule governing each sequence. Let's go through each sequence step by step.

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Sequence 1: 1, 2, __, 8

- The pattern appears to be multiplying by 2.
- \( 1 \times 2 = 2 \)
- \( 2 \times 2 = 4 \)
- \( 4 \times 2 = 8 \)
- Missing number: 4

Sequence 2: 1, 5, __, 13

- The pattern appears to be adding 4 each time.
- \( 1 + 4 = 5 \)
- \( 5 + 4 = 9 \)
- \( 9 + 4 = 13 \)
- Missing number: 9

Sequence 3: 3, 6, __, 12

- The pattern appears to be multiplying by 2.
- \( 3 \times 2 = 6 \)
- \( 6 \times 2 = 12 \)
- Missing number: 9

Sequence 4: 5, __, 15, 20

- The pattern appears to be adding 5 each time.
- \( 5 + 5 = 10 \)
- \( 10 + 5 = 15 \)
- \( 15 + 5 = 20 \)
- Missing number: 10

Sequence 5: __, 9, 27

- The pattern appears to be multiplying by 3.
- \( 3 \times 3 = 9 \)
- \( 9 \times 3 = 27 \)
- Missing number: 3

Sequence 6: __, 16, 32

- The pattern appears to be multiplying by 2.
- \( 8 \times 2 = 16 \)
- \( 16 \times 2 = 32 \)
- Missing number: 8

Sequence 7: 6, 8, __, 20

- The pattern appears to be adding 2, then 4, then 6, and so on.
- \( 6 + 2 = 8 \)
- \( 8 + 4 = 12 \)
- \( 12 + 8 = 20 \)
- Missing number: 12

Sequence 8: 4, 5, __, 10

- The pattern appears to be adding 1, then 2, then 3, and so on.
- \( 4 + 1 = 5 \)
- \( 5 + 2 = 7 \)
- \( 7 + 3 = 10 \)
- Missing number: 7

Sequence 9: 4, 9, 16

- The pattern appears to be squares of consecutive integers.
- \( 2^2 = 4 \)
- \( 3^2 = 9 \)
- \( 4^2 = 16 \)
- Next number: 25 (since \( 5^2 = 25 \))

Sequence 10: 8, 16, 24, 32

- The pattern appears to be adding 8 each time.
- \( 8 + 8 = 16 \)
- \( 16 + 8 = 24 \)
- \( 24 + 8 = 32 \)
- Next number: 40

Sequence 11: 0, 1, 2, 3, __, 5

- The pattern appears to be counting up by 1.
- \( 0 + 1 = 1 \)
- \( 1 + 1 = 2 \)
- \( 2 + 1 = 3 \)
- \( 3 + 1 = 4 \)
- \( 4 + 1 = 5 \)
- Missing number: 4

Sequence 12: 30, 28, 26, __

- The pattern appears to be subtracting 2 each time.
- \( 30 - 2 = 28 \)
- \( 28 - 2 = 26 \)
- \( 26 - 2 = 24 \)
- Missing number: 24

Sequence 13: 16, 12, 8, __

- The pattern appears to be subtracting 4 each time.
- \( 16 - 4 = 12 \)
- \( 12 - 4 = 8 \)
- \( 8 - 4 = 4 \)
- Missing number: 4

Sequence 14: 27, 26, 24, __

- The pattern appears to be subtracting 1, then 2, then 3, and so on.
- \( 27 - 1 = 26 \)
- \( 26 - 2 = 24 \)
- \( 24 - 3 = 21 \)
- Missing number: 21

Sequence 15: 32, 30, 26, 18, __

- The pattern appears to be subtracting an increasing even number: 2, 4, 8, 16, and so on.
- \( 32 - 2 = 30 \)
- \( 30 - 4 = 26 \)
- \( 26 - 8 = 18 \)
- \( 18 - 16 = 2 \)
- Missing number: 2

Sequence 16: 500, 100, 20, __

- The pattern appears to be dividing by 5 each time.
- \( 500 \div 5 = 100 \)
- \( 100 \div 5 = 20 \)
- \( 20 \div 5 = 4 \)
- Missing number: 4

Sequence 17: 48, 24, 12, __

- The pattern appears to be dividing by 2 each time.
- \( 48 \div 2 = 24 \)
- \( 24 \div 2 = 12 \)
- \( 12 \div 2 = 6 \)
- Missing number: 6

Sequence 18: 81, 27, 9, __

- The pattern appears to be dividing by 3 each time.
- \( 81 \div 3 = 27 \)
- \( 27 \div 3 = 9 \)
- \( 9 \div 3 = 3 \)
- Missing number: 3

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Final Answers:

1. 4
2. 9
3. 9
4. 10
5. 3
6. 8
7. 12
8. 7
9. 25
10. 40
11. 4
12. 24
13. 4
14. 21
15. 2
16. 4
17. 6
18. 3

Boxed Answer:
\[
\boxed{4, 9, 9, 10, 3, 8, 12, 7, 25, 40, 4, 24, 4, 21, 2, 4, 6, 3}
\]