hp 17bii

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.