HP 49g+ - Manual (Page 125)

Page 3-3
specification. Real number calculations will be demonstrated in both the
Algebraic (ALG) and Reverse Polish Notation (RPN) modes.
Changing sign of a number, variable, or expression
Use the \ key. In ALG mode, you can press \ before entering the
number, e.g., \2.5`. Result = -2.5. In RPN mode, you need
to enter at least part of the number first, and then use the \ key, e.g.,
2.5\. Result = -2.5. If you use the \ function while there is no
command line, the calculator will apply the NEG function (inverse of sign) to
the object on the first level of the stack.
The inverse function
Use the Ykey. In ALG mode, press Y first, followed by a number or
algebraic expression, e.g., Y2. Result = ½ or 0.5. In RPN mode, enter
the number first, then use the key, e.g., 4`Y. Result = ¼ or 0.25.
Addition, subtraction, multiplication, division
Use the proper operation key, namely, + - * /. In ALG mode,
press an operand, then an operator, then an operand, followed by an ` to
obtain a result. Examples:
3.7 + 5.2 `
6.3 - 8.5 `
4.2 * 2.5 `
2.3 / 4.5 `
The first three operations above are shown in the following screen shot:
In RPN mode, enter the operands one after the other, separated by an `,
then press the operator key. Examples:
3.7` 5.2 +
6.3` 8.5 -
4.2` 2.5 *
2.3` 4.5 /
Alternatively, in RPN mode, you can separate the operands with a space
(
#) before pressing the operator key. Examples: