2/5 : 4 halves in 2/ , and 10 halves in /5. each half = .5 in /2 but the denominator never changes. .5 x 4 = 20 in other words four .5's = 20. So the problem looks like this 20/5 but then you are forced to use the reciprocal of 20/5 which is 5/20 , now divide.