Simply typing 6+6 won't sum the values, but it will work if you put them into a roll: /r 6+6 or [[6+6]] . However, target numbers don't like extra stuff. You shoul be able to combine the roll command and inline rolls: /r d20>[[6+6]] . Another alternative is to subtract the target's modifier from the roll rather than add it to the target: [[{d20-6}>6]] .
