It's already in its simplest form because they are both prime numbers
11 over 13 is in simplest form because they are both prime numbers and cant be divided by anything.
11/13 is already in its simplest form
88/104 = 11/13
33/39 in simplest form is 11/13.
37
It is 13 : 11.
77/91 = 11/13
11/13
11/13
11/13
11/13
11/13