A Simple Proof of a 400-Year Old Theorem about Numbers
Sometimes the simplest proofs give the best insights into how mathematicians think
Fermat’s Little Theorem is a beautiful number-theoretic result which states that, for any integer a and any prime number p, aᵖ﹣a is divisible by p. For example, if a = 4 and p = 3 then aᵖ﹣a = 60 which is divisible by 3.