How can i know which is bigger and which is smaller?

Okay, so the top numbers are how many pieces we have, and the bottom number is how many pieces there are, think of it like a pizza. If the pizza is cut into 8 slices and you have one slice, you have a smaller piece of pizza than one slice from a pizza that was only cut into 6 pieces, which is smaller than one slice from a pizza that was only cut into 3 pieces. The more pieces there are, the smaller the pieces are, so the bigger the bottom number is, the smaller the fraction is.

The bigger the number in the bottom the fraction is getting smaller