Mathematics Help + Utility

Hi!
This is my first app. I know it is really simple and not that useful, but I still wanted to upload it to get some advices on what I could add or fix!
Here is what it does:
-it tells you if a number is prime
-it finds a number's divisors
-it tells you the factorial of a number
-it reduces a fraction to its lowest terms
-it finds the greatest common divisor (G.C.D) of the numbers you write
-it solves quadratic equations

I'll add new features soon!

I am uploading this app for free, so please don't be rude if you decide to rate it :)