Every expression consists of at least one operand and can have one or more operators. Operands are values, whereas operators are symbols that represent particular actions. In the expression
x + 5
x and 5 are operands, and + is an operator.
Expressions are used in programming languages, database systems, and spreadsheet applications. For example, in database systems, you use expressions to specify which information you want to see. These types of expressions are called queries.
Expressions are often classified by the type of value that they represent. For example: