Evaluated First

It is possible to evaluate the argument before it is passed into a subroutine or function.
This can be achieved by enclosing it inside its own parentheses.
This has nothing to do with the Call keyword.

Calling Subroutines

There are two ways to call a subroutine.
The first is to use the Call keyword in which case the arguments have to appear in parentheses.
The second is to not use the Call keyword in which case the arguments DO NOT have to appear in parentheses.

You can enclose arguments inside there own set of parentheses to force them to be evaluated first.

If you are not using the Call keyword this implicit evaluation is harder to spot.

Example

The following snippets demonstrates that when you enclose your variables in parentheses you get different results.
You should always try and use the Call keyword when you are passing control to a subroutine to avoid confusion.