# Chapter 3 - Calculations With Real Numbers; Examples Of Real Number Calculations - HP 50g 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, \2.5`.
In RPN mode, e.g., 2.5\.
• Use the Ykey to calculate the inverse of a number.
For example, in ALG mode, Y2`.
In RPN mode use 4Y.
• For addition, subtraction, multiplication, division, use the proper
operation key, namely, +-*/.
Examples in ALG mode:
Examples in RPN mode:
Alternatively, in RPN mode, you can separate the operands with a
space (#) before pressing the operator key. Examples:
Page 3-1
3.7+5.2`
6.3-8.5`
4.2*2.5`
2.3/4.5`
3.7` 5.2+
6.3` 8.5-
4.2` 2.5*
2.3` 4.5/
3.7#5.2+  