# Mathematics Functions; Percentage Functions - HP 12C Platinum User Manual

Financial calculator.

236 Appendix A: RPN and the Stack

## Mathematics Functions

To perform an arithmetic operation, the numbers are positioned in the X- and
Y-registers just as you would write them vertically on paper: the number you would
write on top goes in the Y-register, and the number you would write on the bottom
goes in the X-register. For example, to do each of the four arithmetic calculations
shown below, you would put the 8 in the Y-register (using \ and then key the 2
into the displayed X-register.)
When an arithmetic operation or q is performed, the answer is placed in the
X-register, the number formerly in the X-register is copied into the LAST X register,
and the stack drops. When the stack drops, the number in the Z-register is copied
into the Y-register, and the number in the T-register is copied into the Z-register but
also remains in the T-register.
The diagram on the next page illustrates the stack operation when 8 ÷ 2 is
calculated. (Assume that the stack and LAST X registers have already been loaded
with the numbers shown as the result of previous calculations.)

### Percentage Functions

When any of the three percentage functions is performed, the answer is placed in
the X-register, the number formerly in the X-register is copied into the LAST X
register, but the stack does not drop. The numbers in the Y-, Z-, and T-registers are
not changed when a percentage function is performed.  