LCM(81, 72) = 648
LCM is equal to the product of the common prime factors on the left and the left-overs on the bottom.
LCM(81, 72) = 3 . 3 . 9 . 8 = 648
Common multiples of 81 and 72 are 648, 1296, 1944 ...
The least common multiple (LCM) of two positive whole numbers is the smallest number that is divisible by these numbers. LCM can be found by using the upside-down cake method. It is equal to the product of the common prime factors listed on the left and the leftovers on the right.