Is 14/25 greater then 1/2

Yes.

You have to change the fractions into fractions with common denominators, so the common denominator is 50. 25 can go into 50 2 times, so you do numerator x 2 which 14/25 is now 28/50. Two can go into 5 25 times, so you put 1/2 as 25/50. 25 is less than 28