Fill in the blank: 0.00187 × ……… = 18.7
2011
Fill in the blank: 0.00187 × ……… = 18.7
Answer: C. 10000 — Concept: Multiplying a decimal by a power of 10 (10, 100, 1000, …) shifts the decimal point to the right by exactly as many places as there are zeros in that…
- A.
100
- B.
1000
- C.
10000
- D.
100000
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Correct answer: C
Concept: Multiplying a decimal by a power of 10 (10, 100, 1000, …) shifts the decimal point to the right by exactly as many places as there are zeros in that power of 10 — equivalently, the missing factor equals (target value) ÷ (given decimal).
Application:
Set up the equation: 0.00187 × y = 18.7, so y = 18.7 ÷ 0.00187.
Clear the decimals by multiplying numerator and denominator by 100000: y = (18.7 × 100000) ÷ (0.00187 × 100000) = 1,870,000 ÷ 187.
Divide: 187 × 10,000 = 1,870,000, so y = 10,000.
Cross-check: Multiplying 0.00187 by 10,000 shifts its decimal point 4 places to the right (as many places as the zeros in 10,000): 0.00187 → 0.0187 → 0.187 → 1.87 → 18.7, which matches the target value exactly.