The Highest Common Factor (HCF) – sometimes called the Greatest Common Factor – of a pair of numbers is the largest whole number which is a factor of both. Greatest_common_factor

Screen Shot 2015-04-11 at 2.06.38 pm




The Lowest Common Multiple (LCM) of two whole numbers is the smallest whole number which is a multiple of both.

Screen Shot 2015-04-11 at 2.08.31 pm