Multiplying Decimals Worksheets - Math Monks - Free Printable

Let's solve each of the decimal multiplication problems step by step. The key to multiplying decimals is:

1. Ignore the decimal points and multiply the numbers as if they were whole numbers.
2. Count the total number of decimal places in both numbers.
3. Place the decimal point in the product so that it has the same number of decimal places as the total from step 2.

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Problem 1: 7.4 × 2.3

- Multiply: 74 × 23 = 1702
- Count decimal places: 1 (in 7.4) + 1 (in 2.3) = 2
- Place decimal: 17.02

✔ Answer: 17.02

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Problem 2: 2.88 × 16.33

- Multiply: 288 × 1633 = ?
- Let’s compute:
- 288 × 1600 = 460,800
- 288 × 33 = 9,504
- Total = 460,800 + 9,504 = 470,304
- Count decimal places: 2 (in 2.88) + 2 (in 16.33) = 4
- Place decimal: 47.0304

✔ Answer: 47.0304

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Problem 3: 15 × 0.73

- Multiply: 15 × 73 = 1095
- Count decimal places: 0 (in 15) + 2 (in 0.73) = 2
- Place decimal: 10.95

✔ Answer: 10.95

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Problem 4: 0.89 × 0.53

- Multiply: 89 × 53 = 4717
- Count decimal places: 2 + 2 = 4
- Place decimal: 0.4717

✔ Answer: 0.4717

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Problem 5: 82 × 0.86

- Multiply: 82 × 86 = ?
- 80 × 86 = 6,880
- 2 × 86 = 172
- Total = 7,052
- Decimal places: 0 + 2 = 2
- Place decimal: 70.52

✔ Answer: 70.52

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Problem 6: 0.133 × 0.478

- Multiply: 133 × 478
- First, 133 × 400 = 52,800
- 133 × 70 = 9,310
- 133 × 8 = 1,064
- Total = 52,800 + 9,310 + 1,064 = 63,174
- Decimal places: 3 + 3 = 6
- Place decimal: 0.063174

✔ Answer: 0.063174

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Problem 7: 39.04 × 6.86

- Multiply: 3904 × 686
- This is a large multiplication; let's break it down:
- 3904 × 600 = 2,342,400
- 3904 × 80 = 312,320
- 3904 × 6 = 23,424
- Add them: 2,342,400 + 312,320 = 2,654,720 + 23,424 = 2,678,144
- Decimal places: 2 + 2 = 4
- Place decimal: 267.8144

✔ Answer: 267.8144

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Problem 8: 22.29 × 19.31

- Multiply: 2229 × 1931
- Break it down:
- 2229 × 1900 = 2229 × 19 × 100 = (42,351) × 100 = 4,235,100
- 2229 × 10 = 22,290
- 2229 × 9 = 19,961
- Sum: 22,290 + 19,961 = 42,251 → wait, correction:
Actually: 2229 × 19 = ?
- 2229 × 10 = 22,290
- 2229 × 9 = 19,961
- Total = 22,290 + 19,961 = 42,251 → then ×100 = 4,225,100
- 2229 × 31 = ?
- 2229 × 30 = 66,870
- 2229 × 1 = 2,229
- Total = 69,099
- Now sum: 4,225,100 + 69,099 = 4,294,199
- Decimal places: 2 + 2 = 4
- Place decimal: 429.4199

✔ Answer: 429.4199

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Problem 9: 0.007 × 1.7

- Multiply: 7 × 17 = 119
- Decimal places: 3 (in 0.007) + 1 (in 1.7) = 4
- Place decimal: 0.0119

✔ Answer: 0.0119

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✔ Final Answers:

| Problem | Answer |
|--------|----------------|
| 1 | 17.02 |
| 2 | 47.0304 |
| 3 | 10.95 |
| 4 | 0.4717 |
| 5 | 70.52 |
| 6 | 0.063174 |
| 7 | 267.8144 |
| 8 | 429.4199 |
| 9 | 0.0119 |

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