Both numbers can be divided by 3.
Do so and you get;
4/19 (four nineteenths)
57/10 cannot be simplified.
27/57 = 9/19
57/76 = 3/4
57/42 = 19/14
12/57 can be simplified to 4/19
19/23
2/19
1/3
57/200 is.
21/57 = 7/19
12 over 91 can't be simplified.
57/5 is in its simplest form.