HP 12c Platinum Quick Start Manual page 13

Table 1-2 RPN Example
Keys
3R4;
5R6;
Y
Display/Description
Enters numbers and operation from the first set
of parentheses. The sum, 7, is displayed and
stored in the X-register.
Enters the numbers and operation from the
second set of parentheses. The sum, 1 1, is
stored in the X-register and displayed, and 7
moves up to the Y-register.
Finishes the operation and displays the results.
Stores 77 in the X-register.
Getting Started 9