Explanation:
We are multiplying decimals by whole numbers. The key idea is:
- Multiply the numbers as if they were whole numbers (ignore the decimal at first).
- Then, count how many digits are after the decimal point in the original decimal number.
- Put the decimal point in the answer so that it has the same number of digits after the decimal.
Let’s solve each one step by step:
1) 16.0 × 8
→ 16.0 is the same as 16 (since .0 doesn’t change value).
16 × 8 = 128
So answer:
128.0 or just
128
2) 45.3 × 4
→ First, ignore decimal: 453 × 4 = 1812
→ 45.3 has 1 digit after decimal → put decimal back after 1 digit from right:
181.2
3) 14.7 × 2
→ 147 × 2 = 294
→ One decimal place →
29.4
4) 39.9 × 3
→ 399 × 3 = 1197
→ One decimal place →
119.7
5) 75.1 × 9
→ 751 × 9 = 6759
→ One decimal place →
675.9
6) 14.9 × 5
→ 149 × 5 = 745
→ One decimal place →
74.5
7) 58.0 × 5
→ 58.0 = 58
58 × 5 = 290
→ So answer:
290.0 or
290
8) 89.9 × 4
→ 899 × 4 = 3596
→ One decimal place →
359.6
9) 23.3 × 1
→ Anything × 1 is itself →
23.3
Let me double-check a few to be safe:
- #2: 45.3 × 4 → 40×4=160, 5×4=20, 0.3×4=1.2 → 160+20+1.2 = 181.2
✔
- #5: 75.1 × 9 → 75×9=675, 0.1×9=0.9 → 675.9
✔
- #8: 89.9 × 4 → 90×4=360, minus 0.1×4=0.4 → 360 − 0.4 = 359.6
✔
All correct.
Final Answer:
1) 128
2) 181.2
3) 29.4
4) 119.7
5) 675.9
6) 74.5
7) 290
8) 359.6
9) 23.3
Parent Tip: Review the logic above to help your child master the concept of multiplying decimals practice worksheet.
