A function is one of the most fundamental ideas in mathematics. At its core, a function describes a rule that takes an input and assigns it exactly one output. You can think of it as a machine: you put a value in, the function processes it according to a fixed rule, and a result comes out. This idea allows mathematicians to describe relationships between quantities, such as how distance depends on time or how the area of a shape depends on its dimensions. Functions help turn real-world situation

Function Notation - What is it? And How to Evaluate Functions

Function Notation and Evaluating Functions - Equations | Algebra 1 Lesson

Function Notation and Evaluating Functions