NeoCal for Pocket PC User Guide
Using NeoCal with Other Applications
The complete state of the calculator is maintained so that you can switch from NeoCal in the middle of a calculation, bring up another application, and then return to NeoCal and finish the calculation.
NeoCal also supports the copy and paste commands allowing you to exchange numbers with other applications. When pasting into NeoCal, the first recognizable number is extracted from any surrounding text.