I'm not exactly great at maths but I know 1/2 is greater than 1/3 because basically the denominator (bottom number) is smaller. Think of it as a piece of cake (this is the basic way off explaining it) you cut it into 2 equal pieces. You then get another cake and cut it into 3 equal pieces. The cake split into to two will have bigger pieces as it has only been split into two and the cake split into 3 will have smaller pieces because there are more of them.