'cal can help me in the command line or the tooltip in some cases, like my example drawing a circle. But drawing a line for example, selecting the first point and polar snapping the horizontal, and entering a length. When using cal it messes up the polar snap for the line angle.

Also you can't use cal in a property inspector field.

I'm sure I'm supposed to be able to enter =250+250 anywhere. So I am hoping I just have to change some system variable.