1) Find the Highest common factor (HCF) of 28 and 63 by expressing them as prime factors.
28=47=227 63=97=337 The number that occurs in both is the HCF (if the same number appears twice or more in both put it to the power of x where x is the number of occurrences)
In this we can see that the HCF is 7, therefore you can divide both the numbers by 7.
28/63 ----> 4/9 4=22 9=33
There are no matching numbers for 4 and 9 therefore that is the fraction in its simplest form.
