5-[2 1/8-(1 3/8-3/4)-5/8]

First we simplify the innermost parentheses:

1 3/8 - 3/4
= 4/8 + 3/8 - 3/4
= 7/8 - 3/4
= 7/8 - 6/8
= 1/8

Now we substitute this back into the original expression:

2 1/8 - 1/8
= 17/8 - 1/8
= 16/8
= 2

Now the expression becomes:

5 - (2 - 5/8)
= 5 - 2 + 5/8
= 3 + 5/8
= 3 5/8

So, 5-[2 1/8-(1 3/8-3/4)-5/8] simplifies to 3 5/8.