Just want to share with you short tip: if you want to have a different representations of negative numbers in the report, it is easy to do using format file in control properties.
So if you have negative numbers with "-" sign, like here:
You can change format in control Properties.
For that example, if you want to show it in brackets (1) instead of -1, than just use following mask:
As you can see here, negative representation is specified after ";" sign.
Masks are related to standard .NET formatting rules.
And than you can check it in browser.
Have a fast reporting!