Homework.Cls

\documentclass[letterpaper]{homework}

\author{Your Name}          % Your name
\identifier{yname1}         % Your email or other identifier
\coursecode{PHYS 999}       % Department and course number
\instructor{Prof.~Feynman}  % The instructor
\assignment{HW 1}           % Assignment identifier

\begin{document}

\problem
Here is the answer to the first problem.
Problem numbers are automatically incremented.
You can begin the next problem with \texttt{\textbackslash problem}.

\problem
\begin{subparts}
    \subpart This problem has several sub-parts
    \subpart They work like \texttt{enumerate} environments
    \subpart and sub-parts can have
    \begin{subparts}
        \subpart sub-sub-parts
        \subpart as needed.
    \end{subparts}
\end{subparts}

\problem
\begin{subparts}[\bf (A.)]
    \subpart You can change the label type as needed
    \subpart and it will be automatically continued
\end{subparts}

\problem
Enjoy!

\end{document}