Brief introductions to essential Olympiad topics, including: Algebra Combinatorics Geometry Number Theory

The author, Geoff Smith, has publicly said he’s fine with students sharing the book for educational use within a small group, but large-scale PDF distribution would harm UKMT’s charitable work. If you like the primer, consider buying a copy — the royalties support UK Olympiad training.

Many beginners find geometry difficult; the primer provides a gentle introduction to these proofs.