• The 12c Platinum, a second calculator in the app: menu → Calculator. It adds an ALG mode with parentheses, undo, backspace, x², 400 program lines and 80 cash flows, on its own face and back plate. The 12C and the Platinum each keep their own memory. • On the 12C: RCL g 12× and RCL g 12÷; storing n, i, PV, PMT or FV no longer stops the stack from lifting; the depreciation amounts and the principal part of AMORT are rounded as on the calculator. • The faces drawn for the screen are cleaner: no lighter box around the keys.

The HP 12C has been the financial calculator of bankers, real-estate agents, accountants and finance students since 1981 — still made today, still allowed in the CFP and CFA exams, still on countless desks. RPN 12C puts one on your iPhone, iPad and Mac, with the face, the keyboard and the display of the real thing. RPN 12C is a new simulator written from the calculator's owner's handbook, every worked example of the handbook serving as a test: it computes as the 12C does, to its ten digits…