# What is a Function? > This section defines a function. Paper 1 Functions and Graphs is about 35 marks; start here with the test a marker uses before any sketch or f(x) algebra: each input x maps to exactly one output y… - Page: https://www.hlayiso.com/grade-12/mathematics/notes/functions-and-graphs/what-is-a-function Breadcrumbs: [Home](https://www.hlayiso.com/) › [Grade 12](https://www.hlayiso.com/grade-12) › [Mathematics](https://www.hlayiso.com/grade-12/mathematics) › [Notes](https://www.hlayiso.com/grade-12/mathematics/notes) › [Functions and graphs](https://www.hlayiso.com/grade-12/mathematics/notes/functions-and-graphs) › [What is a Function?](https://www.hlayiso.com/grade-12/mathematics/notes/functions-and-graphs/what-is-a-function) ## Full notes This is a preview of the What is a Function? notes for Grade 12 Mathematics. Create a free Hlayiso account to read the full notes, practise every question and track your progress. ## More in Functions and graphs - [Function Notation](https://www.hlayiso.com/grade-12/mathematics/notes/functions-and-graphs/function-notation) — Next section - [All Functions and graphs sections](https://www.hlayiso.com/grade-12/mathematics/notes/functions-and-graphs) ## Frequently asked questions ### What will I learn in "What is a Function?"? This section covers What is a Function? as part of Functions and graphs in Grade 12 Mathematics. You'll find clear explanations, worked examples, and key definitions aligned to the CAPS curriculum. ### Is this section aligned with the CAPS curriculum? Yes. All notes on Hlayiso, including "What is a Function?", are written against the official CAPS curriculum and ATP for Grade 12 Mathematics. ### What should I study after "What is a Function?"? Continue with the next section in Functions and graphs, or test your understanding with the interactive quiz linked to this section. --- Hlayiso: free CAPS and IEB past papers, memos, notes and study guides for South African learners. When citing, link the page URL above, not a PDF or /api/ URL.