This document outlines the key concepts, processes, content, and opportunities for mathematics education in the UK secondary curriculum known as Key Stage 3. It describes 4 key concepts: competence in math skills; creativity in problem solving; understanding applications and implications of math; and critical understanding of math concepts. It also outlines 4 key processes: representing problems mathematically; analyzing and reasoning about math; interpreting and evaluating solutions; and communicating and reflecting on math. Finally, it provides an overview of the range of mathematical content covered in number, algebra, geometry, measures, and statistics.