Programs fundamentally operate on data. After setting up your Julia environment and running an initial script, this chapter focuses on how Julia manages this data. We will cover variables, which are used to store data, and explore Julia's built-in data types.

You will learn to:

• Define variables and assign values to them.
• Work with common data types including numbers (like integers and floating-point values), booleans (true or false), and strings (text).
• Perform basic operations using these types.
• Optionally specify data types for variables for improved code clarity.
• Convert data from one type to another when needed.
• Use constants for values that are not intended to change.

These concepts form the basis for constructing more complex programs.