Method 1 - Make your own evaluator engine...
You could parse the tokens from the infix string you want to evaluate, then convert them to RPN, and evaluate them against a stack.

Do a search on the forums for "Reverse Polish Notation", "Stack", "Calculators" etc.

Method 2 - Use MS Scripting control...
Use the Microsoft Scripting control... Do a search for it on the forums... "Scripting control"

You might want to search thr forum for the following key words as well: Expressions, Infix, Postifx, Evaluating...

Post back if you need more help.

Laterz