Thanks for it but I still need more example because I don know how it really work.

I got anyother question which is I need to know a command that is:

if I press "(" and ")" in the textbox it will start calculate the total for sum in the brackets B+C first like eg.
A (B+C) before it will multiply the A.

I need command and sample for using it.

There is any small problem with the textbox sometime got problem with the int and string stuff so I don like textbox something, but labels can slove it. maybe you got better ideal sloving it.