"The third edition fully covers both Core and Extended content through the 'spiral' approach, where students build on their previous learning as they progress through the course. In addition to a wealth of practice questions and support for English as a second language learners, we have included a number of projects to encourage students to put their theory into practice provided by NRICH – a collaboration between the Faculties of Mathematics and Education at the University of Cambridge. Answers are available on Cambridge GO."