Thank you, Brian and Graham for your replies.
Sorry for asking so many questions about variables. I come from an Ahha system which I still use and have "grown up" on. The Mach. system is somewhat different programming-wise. I need to get used to the differences.
Variables are one of the differences that I need to understand because I use them in quite a few programs. I've found that it simplifies things for future use when I desire to make changes. Actually, I've become comfortable writing code for the Ahha using variables and have a few "canned" programs for drilling and simple pocket routines where all I have to do is change a few variables at the beginning of the program and I can start cutting chips quickly.
Just trying to get to this level with Mach.
I have found one thing of interest that seems awkward with the Mach system. Perhaps you can shed some light. In Ahha a circle could be coded on one line using x,y,i,j. In Mach. if I understand it correclty, a circle has to be programmed as two semi circles. Any reason for this?
I guess you can see where the variables would come in handy.
By the way, Graham, I appreciate your example on how to use one variable and have it change the negative side as well. I'll be using that right along.
Thanks
LEW