# Chapter 3 - Calculations With Real Numbers; Examples Of Real Number Calculations - HP 49g+ User Manual

Graphing calculator.

Chapter 3
Calculations with real numbers
This chapter demonstrates the use of the calculator for operations and
functions related to real numbers. The user should be acquainted with the
keyboard to identify certain functions available in the keyboard (e.g., SIN,
COS, TAN, etc.). Also, it is assumed that the reader knows how to change
the calculator's operating system (Chapter 1), use menus and choose boxes
(Chapter 1), and operate with variables (Chapter 2).

### Examples of real number calculations

To perform real number calculations it is preferred to have the CAS set to Real
(as opposed to Complex) mode. Exact mode is the default mode for most
operations. Therefore, you may want to start your calculations in this mode.
Some operations with real numbers are illustrated next:
Use the
key for changing sign of a number.
\
For example, in ALG mode,
In RPN mode, e.g.,
Use the
k ey to calculate the inverse of a number.
Y
For example, in ALG mode,
In RPN mode use
For addition, subtraction, multiplication, division, use the proper
operation key, namely,
Examples in ALG mode:
Examples in RPN mode:
\ 2 . 5 `
2 . 5 \
Y 2 `
.
4 ` Y
+ - * /
3 . 7 + 5 . 2 `
6 . 3 - 8 . 5 `
4 . 2 * 2 . 5 `
2 . 3 / 4 . 5 `
3 . 7 ` 5 . 2 +
.
.
.
.
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