Think of a pizza. If there are 5 slices and you have all 5 of them, then you have the whole pizza.

Now, instead of the pizza having 5 slices, it now has 10. Since the pizza is still the same size, the pieces are going to smaller. If you have 9 slices out of the 10, you won't have the whole pizza.

This is why 5/5 is greater than 9/10.