Here's a tip for the future, using euclidean algorithm http://en.wikipedia.org/wiki/Euclidean_a... you can find the greatest common divisor of two numbers, which is what you want to use to simplify the number.

Essentially you start out with two numbers you want to find the GCD for and divide the larger by the smaller 488/90 which gives 5*90 and a remainder of 38.

You then take the smaller number of the previous step and divide it by the remainder so 90/38 which gives 2*38 and a remainder of 14

Repeating the process you get 38/14 which is 2*14 with a remainder of 10.

14/10 which is 1*10 with 4 remainder

10/4 which is 2*4 with 2 remainder

and with the last step you get 4/2 which is 2*2 with 0 as the remainder.

Whenever you reach a 0 remainder the last nonzero remainder is the greatest common divisor which in this case is 2.

So dividing 488/2 and 90/2 you get 244/45 as the simplest form.

Checking the result with wolframalpha shows that it's correct http://www.wolframalpha.com/input/?i=488...