No 33 over 54 is not in simplest form. Simplest form is 11 over 18
54/3 = 18/1 = 18
21/54 = 7/18
54
If you mean 18/54 then it is 1/3 in its simplest form
33/54 = 11/18
87/54 = 29/18
Expressed as a proper fraction in its simplest form, by dividing the numerator and denominator by 18, 18/54 is equal to 1/3 or one third.
17/18
17/18
3/54 = 1/18
69/54 = 15/18