I am having a bit of trouble with using the equations in solidworks. The way that I know to use equations is to create a global variable, and then assigning that variable to something like the length of a line. Lets say I have created the variable "B" and assigned the value to be 40mm. Then I smart dimension a line and try to add the variable, the line just smart dimensions to 40mm, and not the "B" variable. I have looked through all the settings and couldn't find anything that would cause this, and I can't find anything online either.