What is the least common multiple of 9 15 and 21?
Prime factorization of 9 = 3x3Prime factorization of 21 = 3x7Prime factorization of 35 = 5x73 is common in P.F. of both 9 and 21. 7 is common in P.F. of both 21 and 35.L.C.M. = Multiplication of common numbers x Multiplication of uncommon numbers L.C.M. = 3x7(common numbers) x 3x5(uncommon numbers) = 21x15 = 315