Chapter 2: Factors, multiples and primes
By the end of this chapter
You will be able to:
- find factors and multiples, and identify prime numbers;
- write a number as a product of prime factors, then use it to find HCF and LCM;
- list possible outcomes in a complete, organised way;
- use the product rule to count choices across several stages.
The chapter problem: making number pairs
A school club has 24 blue counters and 36 red counters. It wants to make identical packs, using every counter, with the same number of each colour in every pack.
How many packs could it make? First, make a low-stakes prediction: do you think there are only one or several possible pack counts? You do not need to work it out yet.
You will use common factors to find the greatest possible number of packs. You will also use organised lists and the product rule to count other choices.
Your turn to connect it
Where have you or someone you know had to split items into equal groups, or count choices across several decisions? Describe one example and say where factors or systematic counting might help.