Is there a way to get Calc to put the decimal point in automatically (like an adding machine)?
No. Whilst this can work well for an adding machine as used for book-keeping, it would be very confusing for a general purpose calculator. A simple solution is to simply work in pence, rather than dollars or pounds. The danger with this is that you forget to enter the zeroes for the pennies when entering a round number of pounds or dollars, especially if you do not use calculators exclusively in this way.
