How do you know what fraction is bigger

Find a common denominator. Typically, the greater the denominator, the smaller the piece.  

To compare fractions, you must first change them so they have the same denominator.

Compare 2/3 and 3/5 and find out which fraction is bigger.

First look at the denominators (the bottom numbers).

Find a new number that both denominators go into:

Try 9 - you can divide 9 by 3 but you can't divide 9 by 5.

Try 10 - you can divide 10 by 5 but not by 3, so that isn't right either.

Try 15 - you can divide 15 by 5 (which equals 3) and you can also divide 15 by 3 (which equals 5), so 15 is the new denominator.

Now you have found a new denominator that is divisable by both numbers, you need to change the numerators (the top numbers).

To change the numerators, simply multiply them by the number of times the denominator goes into 15.

So for 2/3 - 3 goes into 15 five times, so you must multiply the numerator (2) by 5 which equals 10.

And for 3/5 - 5 goes into 15 three times, so you must multiply the numerator (3) by 3 which equals 9.

2 divided by 3 equals 10 divided by 153 divided by 5 equals 9 divided by 1510 divided by 15 is bigger than 9 divided by 152 divided by 3 is bigger than 3 divided by 5

So now both fractions have been changed you can compare them to see which fraction is the biggest. 10/15 is bigger than 9/15 so the biggest original fraction is 2/3.