You can't have tabs in labels, used a string.format trick. Also shaved 64 bits of memory off your code
Tidying up some code, and added cases for all the operators to prevent crashes because of unwritten code
Centralized the calculation step displaying code:
Program.form1.ClearLines() and Program.form1.AddLine()
Issue #3
DOUG READ THE README BEFORE CODING
Done multiplication, and a few display bugs
Cleaning up
Added subtraction