\[ \sum _{n=1}^{\infty }\frac{x^{n}}{n}=\ln \left(\frac{1}{1-x}\right)\] \begin{equation} {\displaystyle }\int _{a}^{b}x^{2}dx=\frac{1}{3}(b-a)^{3}\label{eq2}\end{equation} \begin{equation} f(x)=\left\{ \begin{array}{cc} \log _{8}x & x > 0\\ 0 & x=0\\ \sum _{i=1}^{5}\alpha _{i}+\sqrt{-\frac{1}{x}} & x < 0\end{array} \right.\label{eq3}\end{equation} \[ \int _{-\infty }^{\infty }\frac{dx}{1+x^{2}}=\pi \] \begin{eqnarray} 1 & = & 4-3\label{mathed:fourth-eqn}\\ 2 & = & 7-5\\ 1 & = & e^{2\pi i}\nonumber \\ 16 & \equiv & 2\, (mod\, 7)\label{mathed:fifth-eqn} \end{eqnarray} \begin{eqnarray} 1 & = & 3-2\label{mathed:second-equation}\\ 2 & = & 4-2\\ 4 & \leq & 7. \end{eqnarray} \[ f(x):=\left\{ \begin{array}{ll} \frac{1}{q}, & \mathrm{if}\, x=\frac{p}{q}\, (\mathrm{in}\, \mathrm{lowest}\, \mathrm{terms})\\ 0, & \mathrm{if}\, x\, \mathrm{is}\, \mathrm{irrational}\end{array} \right.\] \[ \left(\begin{array}{ccc} 1 & 2 & 3\\ 4 & 5 & 6\\ 7 & 8 & 9\end{array} \right),\] \[ \left(\begin{array}{ccc} \lambda _{1} & & \\ & \ddots & \\ & & \lambda _{n}\end{array} \right),\] \[ \frac{1}{\left(1+\left(\frac{1}{1+\left(\frac{1}{1+x}\right)}\right)\right)},\] \[ \lim _{x\rightarrow 0}f(x)=L\] \[ E < mc^{2},\] \[ a < b > c,\] \[ a\leq b\geq c.\] \begin{eqnarray*} -D(p\Vert q) & = & \sum _{x}p(x)\ln {\frac{q(x)}{p(x)}}\\ & \leq & \sum _{x}p(x)({\frac{q(x)}{p(x)}}-1)\\ & \leq & 0 \end{eqnarray*} \[ a < b > c\] $ > > $ $ \backslash $ $ < $ $ < < $ $ < $ $ < < $ $ < < $ $ < $ $ < < $ $ > > $ $ \sum _{n=0}^{\infty }\frac{1}{n!}=e$ $ \int _{a}^{x}f(t)dt:=F(x)$ $ D(p\Vert q)\geq 0$ $ \ln x\leq x-1$ $ 0 < x < \infty .$ $ b$ $ < $ $ > $ $ < $ $ > $ $ \rightarrow $ $ \rightarrow $ $ \rightarrow $ $ \rightarrow $ $ < < $ $ > > $