Question

Evaluate (101.5)²-(100.5)²​

Answer 1

You can exploit the difference-of-squares identity,

a² - b² = (a - b) (a + b)

Then

101.5² - 100.5² = (101.5 - 100.5) * (101.5 + 100.5)

101.5² - 100.5² = 1 * 202

101.5² - 100.5² = 202