Sometimes you are given numbers expressed as a product of prime factors. For example, 8 = 2 3 and 90 = 2 × 3 2 × 5. If you want to find the LCM and HCF in an exam, we can use prime factor form ...

The highest common factor (HCF) is found by identifying all common factors of two numbers ... 2 and 4. The highest common factor is 4. The lowest common multiple (LCM) is found by listing ...