[SamAdams76]

The iPhone has apps that emulate all those old HP calculators.

As well, the superior processing power of the iPhones makes them run even faster.

Another hidden trick, when in the iPhone calculator app, rotate the phone into landscape orientation and many of the advanced functions of the HP calculators will appear.

[DoodleBob]

The one advantage to the 12c iPhone app (I bought the official one, not a knockoff..I'm a geek that way) is the IRR calc is instantaneous vs the hand-held "running..." message as it iterates to an answer. But the physical buttons and indestructible engineering of that little beast keeps it in my briefcase.

Re: landscape the iPhone calculator view. When I saw that the first time, it blew my mind. For me, the "1/X" button helps bigly and with y^x I can do CAGR calculations on the fly.