ARITHMETIC 1

Evaluate 396² – 386²

Solution

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

396² – 386²  = (396 + 386)( 396 – 386)

                   = (782)( 10)

                   = 7820   [only add a zero at 782]

396² – 386² = 13820

TRY THIS…………….

  

Evaluate 508² – 408²