aSSo is a 32-bit
all-purpose calculator that also accepts expressions and functions. It
includes all mathematical and financial functions, as well as calendar
computing. Its RPN function lets you compute the interest rate of any cash
transaction. You can calculate the real interest rate of loans, investments,
saving accounts, leasing, and more and even convert numbers between 120
different measures, grouped in 12 categories. aSSo! also lets you
expressions that you can introduce as you write them, let you see graphs and
compute derivates and integrals, get the solution of equations up to the
sixteenth gradient, and do complex and vectorial calculations. Select from
an English, Italian, Spanish, or German interface.

aSSo- is the Shareware version. The full version can be purchased by clicking on the "CLICK HERE TO ORDER" button below for around  30.00USD.