User:Dgarber/Sandbox

$ \frac{2}{3} + \frac{3}{4} = \frac{5}{9}. $

$x$ is an integer, then $x^{2 + 3} = (x^2)^3$

$n \in \NN$, and $n \geq 1$, then $\sum_{i=1}^{n+3} i = i^2$.