template.tex

\documentclass{article}
\usepackage{amsmath, amssymb, mathtools, tikz, enumitem, fancyhdr, mleftright, wrapfig, scrextend}
\usetikzlibrary{calc}
\usepackage[margin = 1in]{geometry}

\def\class{CLASS}
\def\discussion{DISCUSSION}
\def\header{TITLE}
\def\first{FIRST}
\def\last{LAST}

\fancypagestyle{first}
{
	\fancyhf{}
	\setlength{\headsep}{\baselineskip}
	\lhead{\class{} - Section \discussion}
	\chead{\header}
	\rhead{\last, \first}
	\cfoot{\thepage}
}

\thispagestyle{first}

%%%%%%%%%%%%Commands%%%%%%%%%%%%
\newcommand{\diff}[1]{\mathrm{d}#1}    % Upright differential
\newcommand{\qed}{\hfill$\blacksquare$}
\DeclarePairedDelimiter{\paren}{(}{)}
\DeclarePairedDelimiter{\brac}{[}{]}
\DeclarePairedDelimiter{\set}{\{}{\}}
\newcommand{\zerospace}
{
	\setlength{\abovedisplayskip}{0pt}
	\setlength{\belowdisplayskip}{0pt}
	\setlength{\abovedisplayshortskip}{0pt}
	\setlength{\belowdisplayshortskip}{0pt}
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%Environments%%%%%%%%%%
\newenvironment{problem}[1]    % Problem environment
{
	\begin{enumerate}[leftmargin = 0in]
		\item[\bfseries{#1}]
}
{	\end{enumerate}
}
\newenvironment{multipart}
{
	\begin{enumerate}[leftmargin = *, align = left, label = {\alph*.}, topsep = 0pt]
}	
{
	\end{enumerate}
}
\newenvironment{proofcase}[1]
{
	\par
	#1
	\begin{addmargin}[1em]{0em}
}
{	
	\end{addmargin}
}
%%%%
\newenvironment{solution}    % Solution environment
{
	\begin{enumerate}[leftmargin = 0in]
		\item[\bfseries{Solution}]
}
{
	\end{enumerate}
}
%%%%
\newenvironment{nospaceflalign*}    % No extra vertical space before flalign* environment
{
	\setlength{\abovedisplayskip}{-\baselineskip}
	\csname flalign*\endcsname
}
{
	\csname endflalign*\endcsname
}
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

%%%%%%%%%%%Homework%%%%%%%%%%%%%
\begin{document}

	\begin{problem}{4.3.14}
		Problem here
	\end{problem}
	
	\begin{solution}
		Solution
	\end{solution}
	
\hrule %%%%%%%%%%%%%%%%%%%%%%%%%

	\begin{problem}{4.3.22}
		Multiple part problem
		\begin{multipart}
			\item First part
			\item Second part
		\end{multipart}
	\end{problem}

	\begin{solution}
		Solution
	\end{solution}
	
\hrule %%%%%%%%%%%%%%%%%%%%%%%%%

	\begin{problem}{4.6.20}
		Multiple cases
		\begin{proofcase}{Case 1:}
			This is the first case.
		\end{proofcase}
		\begin{proofcase}{Case 2:}
			This is the second case.
		\end{proofcase}
		This is the end of the proof. \qed
	\end{problem}

	\begin{solution}
		Solution
	\end{solution}
	
\end{document}