Numeracy: Number sequences | Worksheet | PrimaryLeap.co.uk - Free Printable

Let's solve each of the number sequences step by step and determine the missing numbers and the rule for each.

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1) 5, 10, 20, ____, ____, ____, ____

- Pattern:
5 → 10 (×2)
10 → 20 (×2)
So, it's multiplying by 2 each time.

- Next terms:
- 20 × 2 = 40
- 40 × 2 = 80
- 80 × 2 = 160
- 160 × 2 = 320

✔ Sequence: 5, 10, 20, 40, 80, 160, 320
✔ Rule: Multiply by 2

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2) -10, -25, -40, ____, ____, ____, ____

- Pattern:
-10 → -25 (−15)
-25 → -40 (−15)
So, subtracting 15 each time.

- Next terms:
- -40 − 15 = -55
- -55 − 15 = -70
- -70 − 15 = -85
- -85 − 15 = -100

✔ Sequence: -10, -25, -40, -55, -70, -85, -100
✔ Rule: Subtract 15

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3) 99, 91, 83, ____, ____, ____, ____

- Pattern:
99 → 91 (−8)
91 → 83 (−8)
So, subtracting 8 each time.

- Next terms:
- 83 − 8 = 75
- 75 − 8 = 67
- 67 − 8 = 59
- 59 − 8 = 51

✔ Sequence: 99, 91, 83, 75, 67, 59, 51
✔ Rule: Subtract 8

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4) 0.7, 0.9, 1.1, ____, ____, ____, ____

- Pattern:
0.7 → 0.9 (+0.2)
0.9 → 1.1 (+0.2)
So, adding 0.2 each time.

- Next terms:
- 1.1 + 0.2 = 1.3
- 1.3 + 0.2 = 1.5
- 1.5 + 0.2 = 1.7
- 1.7 + 0.2 = 1.9

✔ Sequence: 0.7, 0.9, 1.1, 1.3, 1.5, 1.7, 1.9
✔ Rule: Add 0.2

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5) 6.4, 6.9, 7.4, ____, ____, ____, ____

- Pattern:
6.4 → 6.9 (+0.5)
6.9 → 7.4 (+0.5)
So, adding 0.5 each time.

- Next terms:
- 7.4 + 0.5 = 7.9
- 7.9 + 0.5 = 8.4
- 8.4 + 0.5 = 8.9
- 8.9 + 0.5 = 9.4

✔ Sequence: 6.4, 6.9, 7.4, 7.9, 8.4, 8.9, 9.4
✔ Rule: Add 0.5

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6) -52, -43, ____, ____, ____, ____

- Pattern:
-52 → -43 (+9)
So, adding 9 each time.

- Next terms:
- -43 + 9 = -34
- -34 + 9 = -25
- -25 + 9 = -16
- -16 + 9 = -7

✔ Sequence: -52, -43, -34, -25, -16, -7
✔ Rule: Add 9

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7) 420, 470, 520, ____, ____, ____, ____

- Pattern:
420 → 470 (+50)
470 → 520 (+50)
So, adding 50 each time.

- Next terms:
- 520 + 50 = 570
- 570 + 50 = 620
- 620 + 50 = 670
- 670 + 50 = 720

✔ Sequence: 420, 470, 520, 570, 620, 670, 720
✔ Rule: Add 50

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8) 26, 66, 106, ____, ____, ____, ____

- Pattern:
26 → 66 (+40)
66 → 106 (+40)
So, adding 40 each time.

- Next terms:
- 106 + 40 = 146
- 146 + 40 = 186
- 186 + 40 = 226
- 226 + 40 = 266

✔ Sequence: 26, 66, 106, 146, 186, 226, 266
✔ Rule: Add 40

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9) -3, -12, -21, ____, ____, ____, ____

- Pattern:
-3 → -12 (−9)
-12 → -21 (−9)
So, subtracting 9 each time.

- Next terms:
- -21 − 9 = -30
- -30 − 9 = -39
- -39 − 9 = -48
- -48 − 9 = -57

✔ Sequence: -3, -12, -21, -30, -39, -48, -57
✔ Rule: Subtract 9

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10) 2, 6, 18, ____, ____, ____, ____

- Pattern:
2 → 6 (×3)
6 → 18 (×3)
So, multiplying by 3 each time.

- Next terms:
- 18 × 3 = 54
- 54 × 3 = 162
- 162 × 3 = 486
- 486 × 3 = 1458

✔ Sequence: 2, 6, 18, 54, 162, 486, 1458
✔ Rule: Multiply by 3

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✔ Final Answers:

| No. | Sequence | Rule |
|-----|-----------------------------------------------|--------------------|
| 1) | 5, 10, 20, 40, 80, 160, 320 | Multiply by 2 |
| 2) | -10, -25, -40, -55, -70, -85, -100 | Subtract 15 |
| 3) | 99, 91, 83, 75, 67, 59, 51 | Subtract 8 |
| 4) | 0.7, 0.9, 1.1, 1.3, 1.5, 1.7, 1.9 | Add 0.2 |
| 5) | 6.4, 6.9, 7.4, 7.9, 8.4, 8.9, 9.4 | Add 0.5 |
| 6) | -52, -43, -34, -25, -16, -7 | Add 9 |
| 7) | 420, 470, 520, 570, 620, 670, 720 | Add 50 |
| 8) | 26, 66, 106, 146, 186, 226, 266 | Add 40 |
| 9) | -3, -12, -21, -30, -39, -48, -57 | Subtract 9 |
|10) | 2, 6, 18, 54, 162, 486, 1458 | Multiply by 3 |

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