39 = 32The least common multiple (LCM) of two numbers is the smallest number (not zero) that is a multiple of both.The number 2 is factor for 4 and 6, HOWEVER it occurs two TIMES for 4, so all the factors are selectedThe number 3 is factor for 6 and 9, however it occurs two times for 9, so both the factors are selectedLCM of 4, 6 and 9 = 22 × 32 = 36