Multiplying Decimals Worksheets - Math Monks - Free Printable

Let’s solve each decimal multiplication problem step by step. We’ll multiply the numbers as if they were whole numbers first, then count how many decimal places are in both numbers together — that tells us where to put the decimal point in the answer.

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Problem 1: 7.4 × 2.3

- Ignore decimals: 74 × 23 = ?
- 74 × 20 = 1480
- 74 × 3 = 222
- Total = 1480 + 222 = 1702
- Decimal places: 7.4 has 1, 2.3 has 1 → total 2 decimal places
- So, 1702 becomes 17.02

✔ Answer: 17.02

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Problem 2: 2.88 × 16.33

- Ignore decimals: 288 × 1633
Let’s break it down:
- 288 × 1600 = 288 × 16 × 100 = (288×10=2880; 288×6=1728 → 2880+1728=4608) ×100 = 460,800
- 288 × 33 = 288×30 + 288×3 = 8640 + 864 = 9504
- Total = 460,800 + 9,504 = 470,304
- Decimal places: 2.88 has 2, 16.33 has 2 → total 4 decimal places
- So, 470304 becomes 47.0304

✔ Answer: 47.0304

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Problem 3: 15 × 0.73

- Ignore decimals: 15 × 73 = ?
- 15 × 70 = 1050
- 15 × 3 = 45
- Total = 1050 + 45 = 1095
- Decimal places: 15 has 0, 0.73 has 2 → total 2 decimal places
- So, 1095 becomes 10.95

✔ Answer: 10.95

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Problem 4: 0.89 × 0.53

- Ignore decimals: 89 × 53
- 89 × 50 = 4450
- 89 × 3 = 267
- Total = 4450 + 267 = 4717
- Decimal places: 0.89 has 2, 0.53 has 2 → total 4 decimal places
- So, 4717 becomes 0.4717

✔ Answer: 0.4717

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Problem 5: 82 × 0.86

- Ignore decimals: 82 × 86
- 80 × 86 = 6880
- 2 × 86 = 172
- Total = 6880 + 172 = 7052
- Decimal places: 82 has 0, 0.86 has 2 → total 2 decimal places
- So, 7052 becomes 70.52

✔ Answer: 70.52

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Problem 6: 0.133 × 0.478

- Ignore decimals: 133 × 478
Let’s compute:
- 133 × 400 = 53,200
- 133 × 70 = 9,310
- 133 × 8 = 1,064
- Total = 53,200 + 9,310 = 62,510 + 1,064 = 63,574
- Decimal places: 0.133 has 3, 0.478 has 3 → total 6 decimal places
- So, 63574 becomes 0.063574 (we need 6 digits after decimal → add leading zero)

✔ Answer: 0.063574

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Problem 7: 39.04 × 6.86

- Ignore decimals: 3904 × 686
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: 39.04 has 2, 6.86 has 2 → total 4 decimal places
- So, 2678144 becomes 267.8144

✔ Answer: 267.8144

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Problem 8: 22.29 × 19.31

- Ignore decimals: 2229 × 1931
This is big — let’s do it carefully:

We can use:
2229 × 1931 = 2229 × (2000 - 69) = 2229×2000 - 2229×69

But maybe easier to do standard multiplication:

Actually, let’s do:

2229 × 1931

Break 1931 into 1000 + 900 + 30 + 1

- 2229 × 1000 = 2,229,000
- 2229 × 900 = 2229 × 9 × 100 = (20,061) × 100 = 2,006,100
- 2229 × 30 = 66,870
- 2229 × 1 = 2,229

Now add:

2,229,000
+2,006,100 = 4,235,100
+66,870 = 4,301,970
+2,229 = 4,304,199

Wait — let me double-check with another method or calculator-style:

Actually, better to verify:

2229 × 1931:

Let me compute 2229 × 1900 = 2229 × 19 × 100

2229 × 19:

2229 × 20 = 44,580 minus 2229 = 44,580 - 2,229 = 42,351 → times 100 = 4,235,100

Then 2229 × 31 = ?

2229 × 30 = 66,870
2229 × 1 = 2,229
Total = 69,099

Now total = 4,235,100 + 69,099 = 4,304,199

Yes.

Decimal places: 22.29 has 2, 19.31 has 2 → total 4 decimal places

So, 4304199 becomes 430.4199

✔ Answer: 430.4199

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Problem 9: 0.007 × 1.7

- Ignore decimals: 7 × 17 = 119
- Decimal places: 0.007 has 3, 1.7 has 1 → total 4 decimal places
- So, 119 becomes 0.0119 (add leading zeros to make 4 decimal places)

✔ Answer: 0.0119

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Final Answer:
1. 17.02
2. 47.0304
3. 10.95
4. 0.4717
5. 70.52
6. 0.063574
7. 267.8144
8. 430.4199
9. 0.0119