Evaluate [(2.39)² − (1.61)²] ÷ (2.39 − 1.61).

Problem restatementSimplify a difference of squares divided by the corresponding difference.

Concept/ApproachUse a² − b² = (a − b)(a + b). Dividing by (a − b) leaves (a + b).

Step-by-Step calculation[(2.39)² − (1.61)²] ÷ (2.39 − 1.61) = 2.39 + 1.61= 4.00

Verification/AlternativeDirect computation of squares is unnecessary once the identity is recognized.

Common pitfallsExpanding both squares numerically instead of applying the identity.

Final Answer4.00