I know that there is the possibility of changing the data type of a
variable, but actually I'm not an expert in conversions...
I thought that declaring the variable digit() As Double could already
solve the problem of converting the string "5" in number 5...

Try with the other approach that I posted. It allows you to work with
numbers instead of strings, and maybe it's better. I don't have time
now to write it in proper code, because I'm just about to leave the
office. But I hope it can be a useful suggestion anyway :-)

See ya!

Antonio.