Mathematics at Key Stage 3 at Saint Felix School [Year 7 (Lower IV), Year 8 (Upper IV) and Year 9 (Lower V)] follows the National Framework for Mathematics. The department uses a dedicated series of text books, supplemented by investigational and practical work together with other proven resources. Pupils are thus well prepared for their two-year GCSE course beginning in Year 10 (Middle V).

In each year group the pupils are set by ability with setting in Year 7 taking place immediately upon entering the school and based on an assessment together with other available information. The opportunity exists at all times for pupil movement between ability sets should current academic progress warrant such a move. In this way we ensure that pupils are able to work at an optimum level.

High achievers within each year group are entered for the appropriate UK National Mathematical Challenge with follow-on rounds available leading to the British Junior Mathematical Olympiad or a European-wide Mathematical Competition taken in over 30 countries.