NavList:

I said *electronic* computation.  Unless our calculator or computer works in D.M.S. format, we will need to convert our D.M.S. sextant reading into decimal degrees format. Some calculators do have a D.M.S. interface, but internally, it's all decinal. Of course, scratching out your answer with pencil and paper doesn't require a conversion, but then, it isn't electronic.

There really isn't much difficulty in converting from D.M.S. to decimal degrees, for either positive or negative angles.  The modest fun begins when converting from decimal degrees back to D.M.S., insuring the proper use of truncation, floor, integer and rounding functions such that the result is proper for both positive and negative angles.  Modest fun is the appropriate phrase!  It's just tricky enough to require some thought, yet not so difficult as to require deep thought.  

Brad