Difficulty: Easy
Correct Answer: 8.31168
Explanation:
Introduction / Context:
Multiplying by 0.999 can be done very quickly by using the identity 0.999 = 1 − 0.001. This method reduces multiplication to a simple subtraction, minimizing rounding errors and mental effort.
Given Data / Assumptions:
Concept / Approach:
Rewrite 0.999 as 1 − 0.001. Then 8.32 × 0.999 = 8.32 × (1 − 0.001) = 8.32 − 0.00832. Simple subtraction then yields the precise product.
Step-by-Step Solution:
0.999 = 1 − 0.001.8.32 × 0.999 = 8.32 − (8.32 × 0.001) = 8.32 − 0.00832.Result = 8.31168.
Verification / Alternative check:
Standard multiplication also gives 8.31168. You can cross-check by noting that the answer must be slightly less than 8.32 (by exactly 0.00832).
Why Other Options Are Wrong:
Common Pitfalls:
Misplacing the decimal when computing 8.32 × 0.001; adding rather than subtracting; copying errors in digits.
Final Answer:
8.31168
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