Thanks for the book advice, i will see if i can hunt a copy down...
I am stuck on one more thing...
My app calculates numbers, some are + and some are -. I need to some how strip the - figures and just make them +, as what i want to do is add them togeather. If it was a - and a - it would be ok, but i have mixed numbers and need to add them all together in a non matchmatical way of plus and minus powers.
Ie
I want -4,5,-2 and 4 to add up to 15.
Any help is appreciated.