An instruction that evaluates to a single value is an expression. An instruction that doesn't is a statement. IDLE is an editor. The interactive shell window has the >>> prompt. The file editor window is where you enter code for complete programs. Data types: int, float, string Strings hold text and begin and end with quotes: ‘Hello world!' Values can be stored in variables: spam = 42 Variables can be used anywhere values can be used in expressions: spam + 1