## 11 June 2018

### Two

$2$ is the only even prime number.

The Fermat's last theorem states that there are no positive integers $x$, $y$ and $z$ such that $x^n+y^n=z^n$ for $n>2$.

$2+2=2\cdot2=2^2$

$2=\left(1+i\right)\left(1-i\right)$

$n^2\pm n$ is always divisible by $2$. Why?