How do I learn RPL and solve this problem with it?

[David Hayden]

What a fantastic problem!!!

For UserRPL programming, download HPUserEdit 6 from hpcalc.org. Also download the file that converts the menus etc into English since the original is in... Spanish? HPUserEdit will let you write and debug your programs on the PC.

If your 50g came with the 184 page "User's Manual" then you should lock that book securely in a safe for now. It's more like a quick reference quide and will only serve to confuse you as a beginner. Use the "User's Guide" instead. It has much more detail.

The biggest problem with the User's Guide has to do with the 4 major modes of operation of the 50g: RPN vs. Algebraic input, and Soft Menus vs. choose boxes. Because of these modes, the User's Guide is full of things that say:

Now to do XYZ in RPN mode, enter these keys (half-page examples follows). If you're using algebraic mode, do this (another half page example follows). The above assume that you're using choose boxes. If you have soft menus, your screens will look like this... and this...

For this reason, you might want to consider using the 48GX User's Guide instead. It's all RPN and all soft menus.