this is one of my favourite hp machines, until recently still
available and is one of the easiest to use.
interestingly, for hp, it can be operated either in rpn or algebraic entry. there is a mode setting for this, which
is remembered. notice the '=' button and parentheses. the '=' button is also
useful in rpn mode. when entering data, into a cash flow calculation, for
example. '=' serves to perform a calculation before input (the input key
is the enter key).
in terms of a scientific calculator it is limited, the math menu
contains only logs, factorial and pi. there are no trig functions, whence
no rad/deg mode. the business functions are comprehensive and it is one of
the easiest, pick up and use, machine for tvm, cashflow, interest
conversion and depreciation. there is also a general formula
solver which is surprisingly straightforward to operate given the machine
has limited alphanumeric input.
the machine itself is slim, pocket sized and fairly well made. i assume
this model was meant to supersede the 12c but it
never completely managed it. this model has been replaced by a remake, the
hp17bii+ 
