Find out about Magic Squares in this article written for students. Why are they magic?!
This article explains various divisibility rules and why they work. An article to read with pencil and paper handy.
This article explains how tree diagrams are constructed and helps you to understand how they can be used to calculate probabilities.
An introduction to the notation and uses of modular arithmetic
Tim Rowland introduces irrational numbers
An introduction to proof by contradiction, a powerful method of mathematical proof.