Trying to mimic a unit converter like this:

http://www.analog.com/en/design-center/interactive-design-tools/dbconvert.html

in smath so I can save it in .exe form.

Is that possible? You can enter a value in any of the boxes, and all the other boxes update accordingly.

Wrote

Is that possible

V:=(π/4)*D²*L

S:=(π/4)*D²

You might use combobox or comboboxlist regions