Ace the CAASPP Math Exam 2026 – Unleash Your Math Mastery!

A variable in mathematical terms is defined as a symbol that represents a missing or unknown value. This representation allows for the formulation of equations and expressions that can model real-world situations and solve problems. Variables are typically denoted by letters, such as x, y, or z, and they can take on different values depending on the context of the problem.

In mathematical equations, using variables gives flexibility and the ability to describe relationships between quantities that may change. For example, in the equation y = 2x + 5, both y and x are variables; y changes as x changes, reflecting that they are not fixed.

The other options do not accurately describe a variable. A fixed number that does not change represents a constant, while a letter or symbol that represents a known value is more akin to a constant than a variable. Lastly, the term used for whole numbers only is incorrect, as variables can represent any type of number, including integers, fractions, and decimals. Therefore, the definition of a variable as a symbol for a missing or unknown value encompasses its essential role in mathematics.