For example if i am using Z7, then first and foremost are the following correct?

-25 = 3

23 = 2

(just want to check im using modulo ok)

Then if i need to simplify 1/2 and 37/2 in Z7, then do i proceed the same? Im just wondering if the numbers have to be integers to use modulo?

At the minute i am thinkin that:

1/2 = 1/2 and

37/2 = 9/2

are these correct?

Thanks :-)