Let’s solve each number sequence step by step. We’ll find the pattern (rule) and then fill in the missing numbers.
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1) 5, 10, 20, __, __, __, __
Look at how we get from one number to the next:
- 5 → 10: multiply by 2
- 10 → 20: multiply by 2
So the rule is:
multiply by 2
Next numbers:
- 20 × 2 = 40
- 40 × 2 = 80
- 80 × 2 = 160
- 160 × 2 = 320
✔ Rule: Multiply by 2
Missing numbers: 40, 80, 160, 320
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2) -10, -25, -40, __, __, __, __
Check the difference between terms:
- -10 to -25: subtract 15 (because -10 - 15 = -25)
- -25 to -40: subtract 15 again
Rule:
subtract 15
Next:
- -40 - 15 = -55
- -55 - 15 = -70
- -70 - 15 = -85
- -85 - 15 = -100
✔ Rule: Subtract 15
Missing numbers: -55, -70, -85, -100
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3) 99, 91, 83, __, __, __, __
Difference:
- 99 → 91: subtract 8
- 91 → 83: subtract 8
Rule:
subtract 8
Next:
- 83 - 8 = 75
- 75 - 8 = 67
- 67 - 8 = 59
- 59 - 8 = 51
✔ Rule: Subtract 8
Missing numbers: 75, 67, 59, 51
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4) 0.7, 0.9, 1.1, __, __, __, __
Difference:
- 0.7 → 0.9: add 0.2
- 0.9 → 1.1: add 0.2
Rule:
add 0.2
Next:
- 1.1 + 0.2 = 1.3
- 1.3 + 0.2 = 1.5
- 1.5 + 0.2 = 1.7
- 1.7 + 0.2 = 1.9
✔ Rule: Add 0.2
Missing numbers: 1.3, 1.5, 1.7, 1.9
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5) 6.4, 6.9, 7.4, __, __, __, __
Difference:
- 6.4 → 6.9: add 0.5
- 6.9 → 7.4: add 0.5
Rule:
add 0.5
Next:
- 7.4 + 0.5 = 7.9
- 7.9 + 0.5 = 8.4
- 8.4 + 0.5 = 8.9
- 8.9 + 0.5 = 9.4
✔ Rule: Add 0.5
Missing numbers: 7.9, 8.4, 8.9, 9.4
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6) -52, -43, __, __, __, __
Wait — only two numbers given? Let’s check:
- -52 → -43: that’s adding 9 (because -52 + 9 = -43)
Assume rule is
add 9
Then:
- -43 + 9 = -34
- -34 + 9 = -25
- -25 + 9 = -16
- -16 + 9 = -7
✔ Rule: Add 9
Missing numbers: -34, -25, -16, -7
*(Note: The problem shows 4 blanks after -43, so we fill 4 numbers.)*
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7) 420, 470, 520, __, __, __, __
Difference:
- 420 → 470: add 50
- 470 → 520: add 50
Rule:
add 50
Next:
- 520 + 50 = 570
- 570 + 50 = 620
- 620 + 50 = 670
- 670 + 50 = 720
✔ Rule: Add 50
Missing numbers: 570, 620, 670, 720
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8) 26, 66, 106, __, __, __, __
Difference:
- 26 → 66: add 40
- 66 → 106: add 40
Rule:
add 40
Next:
- 106 + 40 = 146
- 146 + 40 = 186
- 186 + 40 = 226
- 226 + 40 = 266
✔ Rule: Add 40
Missing numbers: 146, 186, 226, 266
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9) -3, -12, -21, __, __, __, __
Difference:
- -3 → -12: subtract 9 (or add -9)
- -12 → -21: subtract 9
Rule:
subtract 9
Next:
- -21 - 9 = -30
- -30 - 9 = -39
- -39 - 9 = -48
- -48 - 9 = -57
✔ Rule: Subtract 9
Missing numbers: -30, -39, -48, -57
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10) 2, 6, 18, __, __, __
Only 3 blanks shown? Let’s see:
- 2 → 6: multiply by 3
- 6 → 18: multiply by 3
Rule:
multiply by 3
Next:
- 18 × 3 = 54
- 54 × 3 = 162
- 162 × 3 = 486
✔ Rule: Multiply by 3
Missing numbers: 54, 162, 486
*(Note: Problem shows 3 blanks — so we give 3 numbers.)*
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Final Answer:
1) 40, 80, 160, 320 — Rule: Multiply by 2
2) -55, -70, -85, -100 — Rule: Subtract 15
3) 75, 67, 59, 51 — Rule: Subtract 8
4) 1.3, 1.5, 1.7, 1.9 — Rule: Add 0.2
5) 7.9, 8.4, 8.9, 9.4 — Rule: Add 0.5
6) -34, -25, -16, -7 — Rule: Add 9
7) 570, 620, 670, 720 — Rule: Add 50
8) 146, 186, 226, 266 — Rule: Add 40
9) -30, -39, -48, -57 — Rule: Subtract 9
10) 54, 162, 486 — Rule: Multiply by 3
Parent Tip: Review the logic above to help your child master the concept of sequence worksheet grade 5.
