code or source code: The sequence of instructions in a program.

syntax: The set of legal structures and commands that can be used in a particular programming language.

output: The messages printed to the user by a program.

console: The text box onto which output is printed.
Some source code editors pop up the console as an external window, and others contain their own console window.
expression: A data value or set of operations to compute a value.
Examples: 1 + 4 * 3 13

Arithmetic operators we will use:
+ - * / addition, subtraction/negation, multiplication, division % modulus, a.k.a. remainder ** exponentiation

precedence: Order in which operations are computed.
* / % ** have a higher precedence than + -

1 + 3 * 4 is 13

Parentheses can be used to force a certain order of evaluation.

(1 + 3) * 4 is 16