The document outlines the syllabus for Class IX mathematics for the academic session 2011-2012. It is divided into two semesters. The first semester covers chapters on number systems, polynomials, coordinate geometry, introduction to Euclid's geometry, lines and angles, triangles, and Heron's formula. The second semester covers chapters on linear equations in two variables, quadrilaterals, areas of parallelograms and triangles, circles, constructions, statistics, probability, and surface areas and volumes. Mental maths practice is scheduled every Monday based on the concerned topic. Related activities are provided at the end of each chapter.