The highest common factor (HCF) is found by identifying all common factors of two numbers and selecting the largest one. For example, 8 and 12 have common factors of 1, 2 and 4. The highest common ...

The lowest/least common multiple (abbreviated to LCM) is the lowest number that is a multiple of two or more subject-numbers. For example, the common multiples of 4 and 5 are 20, 40, 60, 80 and so on.