% Added by Texmaker
\documentclass[10pt]{book}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage{makeidx}
\usepackage{graphicx}
\usepackage{lmodern}
\usepackage{fourier}
\author{Kenneth John Odle}

% The following is from Overleaf:

% \pdfpagewidth=250mm
% \pdfpageheight=370mm
% \setlength{\hoffset}{0mm}
% \setlength{\voffset}{0mm}
% \setlength{\evensidemargin}{57.1mm}
% \setlength{\oddsidemargin}{20.1mm}
% \setlength{\headheight}{10.0mm}
% \setlength{\headsep}{5.0mm}
% \setlength{\footskip}{12.0mm}
% \setlength{\topmargin}{37.1mm}
% \setlength{\textwidth}{122.0mm}
% \setlength{\textheight}{218.0mm}
% \setlength{\marginparsep}{5.0mm}
% \setlength{\marginparwidth}{35.0mm}

% Added by me
\usepackage{blindtext}
\usepackage{multicol}

\begin{document}

The main difference I've observed so far between the `book` class and the `report` class is that the report document class puts page numbers at the top, and the report document class puts page numbers at the bottom.

\medskip

\blindtext

\blindtext

\blindtext

\begin{multicols}{2}

\blindtext

\blindtext

\blindtext

\end{multicols}

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

\blindtext

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\blindtext

\end{document}