Difficulty: Easy
Correct Answer: 161.3
Explanation:
Introduction / Context:
The classic identity a^2 − b^2 = (a − b)(a + b) is a powerful shortcut, especially with decimals. It replaces squaring and subtracting with two additions/subtractions and one multiplication, greatly reducing error likelihood and saving time.
Given Data / Assumptions:
Concept / Approach:
Apply a^2 − b^2 = (a − b)(a + b). The numbers are chosen so that a − b is an integer, making the product particularly simple to evaluate accurately.
Step-by-Step Solution:
Verification / Alternative check:
Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:
Discussion & Comments