Multiplying Decimals with 1-digit number worksheet - Free Printable

Let's solve each multiplication problem step by step and check if the answers are reasonable. We'll go through each one carefully.

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a) 2.7 × 2

Step-by-step:
- Multiply as if they were whole numbers:
$ 27 × 2 = 54 $
- Now, count decimal places: 2.7 has 1 decimal place.
- So, place the decimal point so that the answer has 1 decimal place:
→ 5.4

✔ Answer: 5.4
✔️ Reasonable? Yes — 2.7 × 2 is just double 2.7, which should be around 5.4.

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b) 5.4 × 3

- $ 54 × 3 = 162 $
- One decimal place in 5.4 → answer has 1 decimal place
- → 16.2

✔ Answer: 16.2
✔️ Reasonable? Yes — 5 × 3 = 15, 5.4 × 3 ≈ 16.2

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c) 0.8 × 3

- $ 8 × 3 = 24 $
- One decimal place → 2.4

✔ Answer: 2.4
✔️ Reasonable? Yes — 0.8 × 3 = 2.4 (like 8 × 3 = 24, then divide by 10)

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d) 23.4 × 4

- $ 234 × 4 = 936 $
- One decimal place → 93.6

✔ Answer: 93.6
✔️ Reasonable? Yes — 20 × 4 = 80, 3.4 × 4 = 13.6 → 80 + 13.6 = 93.6

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e) 14.6 × 5

- $ 146 × 5 = 730 $
- One decimal place → 73.0 or 73

✔ Answer: 73.0 (or 73)
✔️ Reasonable? Yes — 14 × 5 = 70, 0.6 × 5 = 3 → total 73

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f) 20.3 × 6

- $ 203 × 6 = 1218 $
- One decimal place → 121.8

✔ Answer: 121.8
✔️ Reasonable? Yes — 20 × 6 = 120, 0.3 × 6 = 1.8 → 120 + 1.8 = 121.8

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g) 3.24 × 3

- $ 324 × 3 = 972 $
- Two decimal places → 9.72

✔ Answer: 9.72
✔️ Reasonable? Yes — 3 × 3 = 9, 0.24 × 3 = 0.72 → 9 + 0.72 = 9.72

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h) 4.78 × 2

- $ 478 × 2 = 956 $
- Two decimal places → 9.56

✔ Answer: 9.56
✔️ Reasonable? Yes — 4.78 × 2 = about 9.56 (double of ~4.8 is ~9.6)

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i) 2.07 × 3

- $ 207 × 3 = 621 $
- Two decimal places → 6.21

✔ Answer: 6.21
✔️ Reasonable? Yes — 2 × 3 = 6, 0.07 × 3 = 0.21 → 6 + 0.21 = 6.21

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j) 16.35 × 3

- $ 1635 × 3 = 4905 $
- Two decimal places → 49.05

✔ Answer: 49.05
✔️ Reasonable? Yes — 16 × 3 = 48, 0.35 × 3 = 1.05 → 48 + 1.05 = 49.05

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k) 10.83 × 6

- $ 1083 × 6 = 6498 $
- Two decimal places → 64.98

✔ Answer: 64.98
✔️ Reasonable? Yes — 10 × 6 = 60, 0.83 × 6 = 4.98 → 60 + 4.98 = 64.98

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l) 34.98 × 3

- $ 3498 × 3 = 10494 $
- Two decimal places → 104.94

✔ Answer: 104.94
✔️ Reasonable? Yes — 35 × 3 = 105, so 34.98 × 3 ≈ 104.94 (slightly less than 105)

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✔ Final Answers:

| Problem | Answer |
|--------|--------|
| a | 5.4 |
| b | 16.2 |
| c | 2.4 |
| d | 93.6 |
| e | 73.0 |
| f | 121.8 |
| g | 9.72 |
| h | 9.56 |
| i | 6.21 |
| j | 49.05 |
| k | 64.98 |
| l | 104.94 |

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🔍 Summary:

All answers are reasonable, and we verified them using estimation and proper decimal placement.

💡 Tip: Always check your work by estimating first (rounding decimals to nearest whole number), then comparing your exact answer to that estimate.

Let me know if you'd like this formatted as a printable sheet!