This seems to be a problem I have with adjusting the scale on a part. I shrink it, do the adjustments, then enlarge it again. BUT the dimensions are off no matter how carefully I adjust the scale values or make sure I'm still scaling about the same point. For example I take a 2in cube, shrink it by a factor of 0.75, then enlarge it by a scale of 1.25, and the cube is now 1.875in instead the 2in I wanted it to be.

Basically I need the math or formula to accurately shrink or enlarge parts to the same size they were before. Or is there a tool that will simply reverse a scaling automatically?