# Module 1: Variables, Values, and Expressions

## Introduction

Variables, values, and expressions form the basic components of all computer programs. A variable is a storage location in the memory of the computer that is identified by a name and can store values. Values are expressions that cannot be reduced to something simpler, such as a number or a string (i.e., text). In general, expressions can be more complex than values, such as the following expression that captures a computation, `1+2+3`, and which would result in the value `6` when it is evaluated. Note that expressions can also contain variables. For example, let’s assume there is a variable `x` that has been assigned value `10`, then the expression `2*x` will result in the value `20`. While it would be impossible to write programs without values and expressions, variables make the life of a programmer much easier. Hard coding a value in each location it is used would make changing programs very difficult, but variables allow us to make such a change in only one location.

## Module Objectives

• Illustrate how to alert information to the user
• Describe variables for Strings
• Describe variables for Numbers
• Identify legal and illegal variable names
• Apply familiar operators in math expressions
• Apply unfamiliar operators in math Expressions
• Eliminate ambiguity from math expressions

## Learning Resources

• Module 1 Readings: Chapters 1 thru 7 from Myers

## Video

How to get started: