What's bigger 5/6 or 2/3

To compare fractions, you need to get both fractions to have the same denominator. 
The denominators are 3 and 6. Both 3 and 6 can be multiplied by something to get 6.
6 x 1 = 6      and      3 x 2 = 6

First, we'll start with 5/6 to show how this works. 
we are going to multiply 5/6 by 1/1 

5 x 1  = 5
6    1     6

Next, we'll change 2/3 to a denominator of 6. 
we are going to multiply 2/3 by 2/2

2 x 2 = 4
3    2    6

Finally we can compare both fractions because they both have the same denominator. 

5/6 > 4/6 
so
5/6 is greater than 2/3