say I have a variable called "RowNum"
RowNum is being used in sub Add_Sheets. halfway through Add_Sheets the code
calls sub Hide_Rows. there's more code after Add_Sheets calls Hide_Rows.
Hide_Rows also uses a variable called RowNum. In Add_Sheets RowNum = 98, but
in Hide_Rows RowNum=10. When Excel finishes Hide_Rows and returns to
Add_Sheets, will RowNum still be 98?