The following was Submitted by Mike Wilson, designer, Sierra Vista, AZ. I hope it is what you are looking for.
Equations - Variable in an Equation
How to Create a Variable in an Equation
• Start a new part, sketch, draw a line and dimension it.
• Create new equation, and select Add.
• Make this equation first: ("D1@Sketch1" = "D1@Sketch1"+1). Select OK.
• Select Edit All.
• Add this line (before the previous equation): MYVAR=1.
• Change your original equation to this: ("D1@Sketch1" = "D1@Sketch1"+MYVAR).
• Select OK, OK.
It should look like this:
MYVAR=1
"D1@Sketch1"="D1@Sketch1"+MYVAR
-- Submitted by Mike Wilson, designer, Sierra Vista, AZ
Bradley