The easiest way to solve it would be to solve how many times 4 will go into 28, which can easily be done by-
28/4=7
So you now know what 4 was multiplied by to get 28, you then do the same for the denominator (5)-
5*7=35
So you can see that-
4/5=28/35
Since you should always check your answer, either divide 4 by five and 28 by 35 to see if you get the same answer, or simplify both terms, giving you 4/5=4/5
