The Lowest Common Multiple (LCM) is the SMALLEST number that will DIVIDE BY ALL the numbers in question.
E.g. 3, 6, 9, 12, 15 are all multiples of 3. 5, 10, 15, 20, 25 are all multiples of 5.
The lowest number that is in both lists is 15, so 15 is the LCM of 3 and 5.
The Highest Common Factor (HCF) is the BIGGEST number that will DIVIDE INTO ALL the numbers in question.
E.g. 1, 2, 4, 8 are all factors of 8. 1, 2, 3, 4, 6, 12 are all factors of 12. The highest number that is in both lists is 4, so 4 is the HCF of 8 and 12.
For each set of numbers find the LCM.