The lowest common multiple of two numbers is the smallest number that both numbers divide, as opposed to the highest common factor, which is the smallest number that both numbers divide.

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Highest Common Factor (HCF) – Largest number that divides two numbers.

Lowest Common Multiple (LCM) – Smallest number that two numbers divide.

The simplest way to find the lowest common multiple of two numbers is to write down the multiples of the two numbers in two list and find the smallest number in both lists.

Example:

Find the Lowest Common Multiple of 20 and 50

Multiples of 20: 20, 40, 60, 80, 100…

Multiples of 50: 100, 150, 200, 250, 300…

The smallest number in bots lists is 100 so the lowest common multiple of 20 and 50 is 100.

Example:

Find the Lowest Common Multiple of 24 and 36

Multiples of 24: 24, 48, 72, 96, 120…

Multiples of 36: 36, 72, 108, 144, 180…

The smallest number in bots lists is 72 so the lowest common multiple of 24 and 36 is 72.