• 8 Posts
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Joined 4 months ago
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Cake day: July 12th, 2024

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  • I always thought of financial calculators as a sort of gelded single-function function machine and I didn’t really get them. However, that would ignore the vast number of models available from HP, and that their second ever pocket calculator was a financial one. It turns out that solving the time value of money equation is non-trivial, and the work done on that probably paved the way for calculators with a solver.

    The other thing I didn’t appreciate until I had to use it, is that the interface of the 12c - with the 5 buttons in the top left for n, i, pv, pmt and fv is peak user interface. Press once to input data, but a second consecutive press of these buttons will trigger the solve and drop the result into x. It’s perfect, and means you can solve and use all the calculator functions and stack continuously. Most modern methods use a table, which is hard to extract and input information from the calculator.




  • These were such great machines, so far ahead of their time. I had a 3a, and nothing has beaten the Agenda program on it. I think part of the reason it was so good was that it wasn’t a touch screen and the keyboard control was so well thought out, especially tab to bring up a monthly calendar. And what modern calendar has a year view that is useful?