Prime numbers are the basis of our number system. They are the elementary building blocks on which all else stands.  The definition is easy: a number is prime if and only if it is divisible by 1 and itself. The apparent simplicity hides a treasure of interesting, challenging and unproved problems.

PRIMARY: addition, subtraction, multiplication and division; prime factors, sieve of Eratosthenes, patterns in primes, Mersenne numbers and primes.

SECONDARY: plus prime pairs, Euclid’s proof of the infinity of the primes, distribution of primes, the Basel problem.

SIXTH FORM: plus unproved conjectures such as the Goldbach conjecture, the Riemann hypothesis etc.