With the Use Assumptions check box, Geometry Expressions eliminates the absolute value from expressions and determines from the diagram whether the value is positive or negative. Try it with these steps:
| 1. | Select  an output calculation. |
| 2. | Click the Use Assumptions check box. |
| 3. | Click the box again to change back to the previous form. |
Obviously, this tool only has an effect when the expression selected contains an absolute value.