Inserting and Deleting rows while maintaining formula consistency

Hopefully the thread title makes sense.

The problem i'm having is that i'm having a bunch of stuff added together vertically and horizontally and when I insert new rows while the worksheet is unprotected everything is fine, but when i protect the worksheet and insert a new row no formulas doesn't get included.

Also, when to worksheet is protected i'd like the user to be able to delete certain rows but the only way to do that currently is to un-protect the sheet. Is there a way around this too?

Thanks for any help you can give.