Can anyone tell me why when you enter this into a cell

=-187992-213510-828672.8-1025000+828672.8+213510+1025000+187992

The value comes out 2.32831E-10 when it should clearly be 0. I know I can
format the cell to show as 0 but why does it ever show as 2.32831E-10 when it
is impossible to have those numbers equal anything other then 0.


Thank you