The remaining factors go in their respective circles. The LCM is found by multiplying all of the numbers in the Venn diagram together. As there are four 2s and two 5s: LCM = 2 × 2 × 2 × 2 × 5 ...

1 is a common factor of all whole numbers. To find common factors: List the factors of each number. Compare the factors to find numbers that are the same (or common) in each list.