Let’s solve each 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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1. 6.09 × 0.4
- Ignore decimals: 609 × 4 = 2436
- Decimal places: 6.09 has 2, 0.4 has 1 → total 3 decimal places
- Put decimal 3 places from right:
2.436
✔ Check: 6 × 0.4 = 2.4, so 2.436 makes sense.
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2. 0.29 × 0.02
- Ignore decimals: 29 × 2 = 58
- Decimal places: 0.29 has 2, 0.02 has 2 → total 4 decimal places
- Need 4 digits after decimal → add leading zero:
0.0058
✔ Check: 0.3 × 0.02 = 0.006, so 0.0058 is close and correct.
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3. 5.89 × 0.08
- Ignore decimals: 589 × 8 = 4712
- Decimal places: 5.89 has 2, 0.08 has 2 → total 4 decimal places
- Answer:
0.4712
✔ Check: 6 × 0.08 = 0.48, so 0.4712 is reasonable.
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4. 3.98 × 0.01
- Ignore decimals: 398 × 1 = 398
- Decimal places: 3.98 has 2, 0.01 has 2 → total 4 decimal places
- Answer:
0.0398
✔ Check: Multiplying by 0.01 moves decimal two places left → 3.98 → 0.0398 ✔️
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5. 51.4 × 0.07
- Ignore decimals: 514 × 7 = 3598
- Decimal places: 51.4 has 1, 0.07 has 2 → total 3 decimal places
- Answer:
3.598
✔ Check: 50 × 0.07 = 3.5, so 3.598 is good.
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6. 54.8 × 0.08
- Ignore decimals: 548 × 8 = 4384
- Decimal places: 54.8 has 1, 0.08 has 2 → total 3 decimal places
- Answer:
4.384
✔ Check: 55 × 0.08 = 4.4, so 4.384 is very close.
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7. 0.86 × 0.42
- Ignore decimals: 86 × 42
Let’s compute:
86 × 40 = 3440
86 × 2 = 172
Total = 3440 + 172 = 3612
- Decimal places: 0.86 has 2, 0.42 has 2 → total 4 decimal places
- Answer:
0.3612
✔ Check: 0.9 × 0.4 = 0.36, so 0.3612 is perfect.
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8. 0.74 × 0.38
- Ignore decimals: 74 × 38
Compute:
74 × 30 = 2220
74 × 8 = 592
Total = 2220 + 592 = 2812
- Decimal places: 0.74 has 2, 0.38 has 2 → total 4 decimal places
- Answer:
0.2812
✔ Check: 0.7 × 0.4 = 0.28, so 0.2812 is accurate.
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Final Answer:
6.09 × 0.4 = 2.436
0.29 × 0.02 = 0.0058
5.89 × 0.08 = 0.4712
3.98 × 0.01 = 0.0398
51.4 × 0.07 = 3.598
54.8 × 0.08 = 4.384
0.86 × 0.42 = 0.3612
0.74 × 0.38 = 0.2812
Parent Tip: Review the logic above to help your child master the concept of multiplying decimals by decimals worksheet 5th grade.
