which is greater?

think of it as: 

You have a perfectly round pizza, with some friends.

do you get more pizza if you share with 12 people or 13 people?

Oviously 12 right? 

 

fractions are the same.

in this case: 1/12 means cutting 1 into 12 equal pieces 

                    1/13 means cutting 1 into 13 equal pieces 

 

Which one is bigger?

the answer: 1/12.