(20 Oct 21) Highest common factor and Lowest common multiple

GCF - Greatest common factor using the factor tree

List the factors of these numbers to find the Greatest common factor

GCF - Greatest common factor using the factor tree

Using the factor tree method, find the GCF by identifying all pairs of common numbers. Multiply each of these numbers once. In the example below, the pairs are 5, 2 and 2 so we multiply 5 x 5 x 2 to get 20.

Find the Greatest common factors of these pairs of numbers

26, 32

32, 58

25, 37

158, 200

49, 98

Lowest common multiple

List the multiples of these numbers until you find the first one they have in common