Using Variables / Equations

I am new to SW from MDT. Is there a way to assign a variable to adjust a workplane's offset distance or angle? I've figured out how to assign variables to dimensions but I can't seem to adjust new planes I've created with variables.

Also when creating dimensions in sketch mode, is there a way to assign a variable immediately without having to open the equation link first?

Don't forget to use equal-contraint. It is much easier to constrain 10
circles first with equal radius (so they are al same size) and then
constrain one of those circles with your variable. Now all other
circles will follow your variable.