<code>Error: normalsize is not defined: there is probably something wrong with the class file.</code>

begin{document}
documentclass[a4paper,10pt]{article}
usepackage{amsmath,amsthm,amssymb}
usepackage{mathtext}

usepackage[T1,T2A]{fontenc}
usepackage[utf8]{inputenc}
usepackage[english]{babel}

usepackage{graphicx}
usepackage[colorinlistoftodos]{todonotes}
usepackage{lmodern}

title{Text.}

author{sahwar}

date{today}, v1.0

begin{document}
maketitle

begin{abstract}
Text.
end{abstract}

tableofcontents

section{Text.}

Your introduction goes here! Some examples of commonly used commands and features are listed below, to help you get started. If you have a question, please use the help menu (``?'') on the top bar to search for help or ask us a question.

section{Some LaTeX{} Examples}
label{sec:examples}

subsection{Text.}

Comments can be added to the margins of the document using the todo{Here's a comment in the margin!} todo command, as shown in the example on the right. You can also add inline comments:

todo[inline, color=green!40]{This is an inline comment.}

subsection{How to Include Figures}

First you have to upload the image file (JPEG, PNG or PDF) from your computer to writeLaTeX using the upload link the project menu. Then use the includegraphics command to include it in your document. Use the figure environment and the caption command to add a number and a caption to your figure. See the code for Figure ref{fig:cosmology1} in this section for an example.

begin{figure}
centering
includegraphics[width=0.3textwidth]{cosmology1}
caption{label{fig:cosmology1}This image was uploaded to writeLaTeX via the project menu.}
end{figure}

subsection{Text.}

Use the table and tabular commands for basic tables --- see Table~ref{tab:widgets}, for example.

begin{table}
centering
begin{tabular}{l|r}
Item & Quantity \hline
Widgets & 42 \
Gadgets & 13
end{tabular}
caption{label{tab:widgets}An example table.}
end{table}

subsection{The 5 types of beings in the Universe according to (sahwar's) syntheso-integrativism}

LaTeX{} is great at typesetting mathematics. Let $X_1, X_2, ldots, X_n$ be a sequence of independent and identically distributed random variables with $text{E}[X_i] = mu$ and $text{Var}[X_i] = sigma^2 < infty$, and let
$$S_n = frac{X_1 + X_2 + cdots + X_n}{n}
      = frac{1}{n}sum_{i}^{n} X_i$$
denote their mean. Then as $n$ approaches infinity, the random variables $sqrt{n}(S_n - mu)$ converge in distribution to a normal $mathcal{N}(0, sigma^2)$.

subsection{How to Make Sections and Subsections}

Use section and subsection commands to organize your document. LaTeX{} handles all the formatting and numbering automatically. Use ref and label commands for cross-references.

subsection{How to Make Lists}

You can make lists with automatic numbering dots

begin{enumerate}
item Like this,
item and like this.
end{enumerate}
dots or bullet points dots
begin{itemize}
item Like this,
item and like this.
end{itemize}
dots or with words and descriptions dots
begin{description}
item[Word] Definition
item[Concept] Explanation
item[Idea] Text
end{description}

We hope you find writeLaTeX useful, and please let us know if you have any feedback using the help menu above.

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end{document}