HP 50g Graphing Calculator - Manual (Page 114)

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At this point, the screen looks like this:
To see the contents of A, use: L @@@A@@@.
To run program p1 with r = 5, use: L5 @@@p1@@@.
Notice that to run the program in RPN mode, you only need to enter the input
(5) and press the corresponding soft menu key. (In algebraic mode, you need
to place parentheses to enter the argument).
Using the right-shift key ‚ followed by soft menu key labels
In Algebraic mode, you can display the content of a variable by pressing J
@
and then the corresponding soft menu key. Try the following examples:
J‚
@@p1@@ ‚ @@z1@@ ‚ @@@R@@ ‚@@@Q@@ ‚ @@A12@@
Note: In RPN mode, you don’t need to press @ (just J and then the
corresponding soft menu key).
This produces the following screen (Algebraic mode in the left, RPN in the right)