ARITHMETICS 1

Evaluate 696² – 686²

Solution

We apply difference of two squares: a² - b² = (a+b)(a-b)

696² – 686²  = (696 + 686)( 696 – 686)

                   = (1382)( 10)

                   = 13820   [only add a zero at 1382]

696² – 686² = 13820

TRY THIS…………….

Evaluate 808² – 708²