Number Sequences | Interactive Worksheet - Free Printable
Educational worksheet: Number Sequences | Interactive Worksheet. Download and print for classroom or home learning activities.
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Step-by-step solution for: Number Sequences | Interactive Worksheet
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Show Answer Key & Explanations
Step-by-step solution for: Number Sequences | Interactive Worksheet
Let’s go through each number sequence one by one. We’ll look for the pattern — like adding, subtracting, multiplying, or dividing — and then fill in the missing number.
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1. 2, 4, __, 8
Looks like we’re adding 2 each time:
2 + 2 = 4
4 + 2 = 6
6 + 2 = 8 → So missing is 6
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2. 1, 5, __, 13
From 1 to 5 is +4
If we add 4 again: 5 + 4 = 9
Then 9 + 4 = 13 → So missing is 9
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3. 3, 6, __, 12
Adding 3 each time:
3 + 3 = 6
6 + 3 = 9
9 + 3 = 12 → Missing is 9
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4. 5, __, 15, 20
From 15 to 20 is +5
So before 15 should be 10 (because 10 + 5 = 15)
And 5 + 5 = 10 → So missing is 10
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5. 1, __, 9, 27
This looks like multiplying by 3:
1 × 3 = 3
3 × 3 = 9
9 × 3 = 27 → Missing is 3
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6. 4, __, 16, 32
From 16 to 32 is ×2
So before 16 should be 8 (because 8 × 2 = 16)
And 4 × 2 = 8 → Missing is 8
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7. 6, 8, __, 20
From 6 to 8 is +2
If we keep adding 2: 8 + 2 = 10, then 10 + 2 = 12… but that doesn’t reach 20.
Wait — maybe it’s increasing by more? Let’s check differences:
8 - 6 = 2
? - 8 = ?
20 - ? = ?
Try this: Maybe it’s +2, then +4, then +6?
6 + 2 = 8
8 + 4 = 12
12 + 8 = 20? No, 12 + 8 = 20 → Wait, 12 + 8 is 20, but 8 isn’t following +6.
Alternative: Maybe it’s doubling after first step? Doesn’t fit.
Wait — let’s try:
6, 8, ?, 20
What if it’s +2, then +6, then +6? 8+6=14, 14+6=20 → That works!
But why +2 then +6? Not consistent.
Another idea: Maybe it’s 6, 8, 12, 20 — because 6+2=8, 8+4=12, 12+8=20 → adding doubles: +2, +4, +8 → yes!
So missing is 12
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8. 4, 5, __, 10
4 to 5 is +1
If we do +2 next: 5 + 2 = 7
Then 7 + 3 = 10 → Yes! Pattern: +1, +2, +3 → So missing is 7
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9. 4, 9, 16, __
These are squares:
2² = 4
3² = 9
4² = 16
5² = 25 → Missing is 25
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10. 8, 16, 24, 32, __
Each time +8:
8 + 8 = 16
16 + 8 = 24
24 + 8 = 32
32 + 8 = 40 → Missing is 40
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11. 0, 1, 1, 2, 3, 5, __
This is Fibonacci! Each number is sum of two before:
0 + 1 = 1
1 + 1 = 2
1 + 2 = 3
2 + 3 = 5
3 + 5 = 8 → Missing is 8
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12. 30, 28, 26, 24, __
Subtracting 2 each time:
30 - 2 = 28
28 - 2 = 26
26 - 2 = 24
24 - 2 = 22 → Missing is 22
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13. 16, 12, 8, __
Subtracting 4 each time:
16 - 4 = 12
12 - 4 = 8
8 - 4 = 4 → Missing is 4
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14. 27, 26, 24, 21, __
Differences:
27 to 26 = -1
26 to 24 = -2
24 to 21 = -3
So next should be -4: 21 - 4 = 17 → Missing is 17
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15. 32, 30, 26, 18, __
Differences:
32 to 30 = -2
30 to 26 = -4
26 to 18 = -8
Pattern: subtracting double each time: -2, -4, -8 → next is -16
18 - 16 = 2 → Missing is 2
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16. 500, 100, 20, __
Dividing by 5 each time:
500 ÷ 5 = 100
100 ÷ 5 = 20
20 ÷ 5 = 4 → Missing is 4
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17. 48, 24, 12, __
Dividing by 2 each time:
48 ÷ 2 = 24
24 ÷ 2 = 12
12 ÷ 2 = 6 → Missing is 6
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18. 81, 27, 9, __
Dividing by 3 each time:
81 ÷ 3 = 27
27 ÷ 3 = 9
9 ÷ 3 = 3 → Missing is 3
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Final Answer:
1. 6
2. 9
3. 9
4. 10
5. 3
6. 8
7. 12
8. 7
9. 25
10. 40
11. 8
12. 22
13. 4
14. 17
15. 2
16. 4
17. 6
18. 3
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1. 2, 4, __, 8
Looks like we’re adding 2 each time:
2 + 2 = 4
4 + 2 = 6
6 + 2 = 8 → So missing is 6
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2. 1, 5, __, 13
From 1 to 5 is +4
If we add 4 again: 5 + 4 = 9
Then 9 + 4 = 13 → So missing is 9
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3. 3, 6, __, 12
Adding 3 each time:
3 + 3 = 6
6 + 3 = 9
9 + 3 = 12 → Missing is 9
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4. 5, __, 15, 20
From 15 to 20 is +5
So before 15 should be 10 (because 10 + 5 = 15)
And 5 + 5 = 10 → So missing is 10
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5. 1, __, 9, 27
This looks like multiplying by 3:
1 × 3 = 3
3 × 3 = 9
9 × 3 = 27 → Missing is 3
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6. 4, __, 16, 32
From 16 to 32 is ×2
So before 16 should be 8 (because 8 × 2 = 16)
And 4 × 2 = 8 → Missing is 8
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7. 6, 8, __, 20
From 6 to 8 is +2
If we keep adding 2: 8 + 2 = 10, then 10 + 2 = 12… but that doesn’t reach 20.
Wait — maybe it’s increasing by more? Let’s check differences:
8 - 6 = 2
? - 8 = ?
20 - ? = ?
Try this: Maybe it’s +2, then +4, then +6?
6 + 2 = 8
8 + 4 = 12
12 + 8 = 20? No, 12 + 8 = 20 → Wait, 12 + 8 is 20, but 8 isn’t following +6.
Alternative: Maybe it’s doubling after first step? Doesn’t fit.
Wait — let’s try:
6, 8, ?, 20
What if it’s +2, then +6, then +6? 8+6=14, 14+6=20 → That works!
But why +2 then +6? Not consistent.
Another idea: Maybe it’s 6, 8, 12, 20 — because 6+2=8, 8+4=12, 12+8=20 → adding doubles: +2, +4, +8 → yes!
So missing is 12
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8. 4, 5, __, 10
4 to 5 is +1
If we do +2 next: 5 + 2 = 7
Then 7 + 3 = 10 → Yes! Pattern: +1, +2, +3 → So missing is 7
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9. 4, 9, 16, __
These are squares:
2² = 4
3² = 9
4² = 16
5² = 25 → Missing is 25
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10. 8, 16, 24, 32, __
Each time +8:
8 + 8 = 16
16 + 8 = 24
24 + 8 = 32
32 + 8 = 40 → Missing is 40
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11. 0, 1, 1, 2, 3, 5, __
This is Fibonacci! Each number is sum of two before:
0 + 1 = 1
1 + 1 = 2
1 + 2 = 3
2 + 3 = 5
3 + 5 = 8 → Missing is 8
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12. 30, 28, 26, 24, __
Subtracting 2 each time:
30 - 2 = 28
28 - 2 = 26
26 - 2 = 24
24 - 2 = 22 → Missing is 22
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13. 16, 12, 8, __
Subtracting 4 each time:
16 - 4 = 12
12 - 4 = 8
8 - 4 = 4 → Missing is 4
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14. 27, 26, 24, 21, __
Differences:
27 to 26 = -1
26 to 24 = -2
24 to 21 = -3
So next should be -4: 21 - 4 = 17 → Missing is 17
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15. 32, 30, 26, 18, __
Differences:
32 to 30 = -2
30 to 26 = -4
26 to 18 = -8
Pattern: subtracting double each time: -2, -4, -8 → next is -16
18 - 16 = 2 → Missing is 2
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16. 500, 100, 20, __
Dividing by 5 each time:
500 ÷ 5 = 100
100 ÷ 5 = 20
20 ÷ 5 = 4 → Missing is 4
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17. 48, 24, 12, __
Dividing by 2 each time:
48 ÷ 2 = 24
24 ÷ 2 = 12
12 ÷ 2 = 6 → Missing is 6
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18. 81, 27, 9, __
Dividing by 3 each time:
81 ÷ 3 = 27
27 ÷ 3 = 9
9 ÷ 3 = 3 → Missing is 3
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Final Answer:
1. 6
2. 9
3. 9
4. 10
5. 3
6. 8
7. 12
8. 7
9. 25
10. 40
11. 8
12. 22
13. 4
14. 17
15. 2
16. 4
17. 6
18. 3
Parent Tip: Review the logic above to help your child master the concept of sequences worksheet year 5.
