The factors of 20 are: 1, 2, 4, 5, 10, 20. The HCF is therefore 4, as this is the largest number that goes into both 12 and 20. Find the HCF of 42 and 24. The factors of 42 are 1, 2, 3 ...

There are many methods to find the prime factors of a number ... The final answer is \(2^3 \times 5\). Now write 24 as a product of the circled prime numbers, \(2 \times 2 \times 2 \times 3 ...