Step 1: Understand what LCM means. LCM stands for Least Common Multiple, which is the smallest number that is a multiple of two or more numbers.
Step 2: List the multiples of 4. The first few multiples of 4 are: 4, 8, 12, 16, 20, ...
Step 3: List the multiples of 5. The first few multiples of 5 are: 5, 10, 15, 20, ...
Step 4: Find the smallest number that appears in both lists of multiples. The multiples of 4 are 4, 8, 12, 16, 20 and the multiples of 5 are 5, 10, 15, 20.
Step 5: The smallest number that is in both lists is 20.
