Errors using the exam class

I’m running latex 3.14 on OSX 10.15.6 (Catlina)

✗ latex --version
pdfTeX 3.14159265-2.6-1.40.21 (TeX Live 2020)
kpathsea version 6.3.2
Copyright 2020 Han The Thanh (pdfTeX) et al.
There is NO warranty.  Redistribution of this software is
covered by the terms of both the pdfTeX copyright and
the Lesser GNU General Public License.
For more information about these matters, see the file
named COPYING and the pdfTeX source.
Primary author of pdfTeX: Han The Thanh (pdfTeX) et al.
Compiled with libpng 1.6.37; using libpng 1.6.37
Compiled with zlib 1.2.11; using zlib 1.2.11
Compiled with xpdf version 4.02

Below is a MWE of my latex document that uses the exam class.

documentclass{article}
usepackage{exam}
renewcommand{choicelabel}{(thechoice)}

begin{document}

begin{questions}
question
This is question 1
begin{choice}
choice green
choice blue
choice yellow
choice orange
end{choice}

question
This is question 2
begin{choice}
choice 6
choice 7
choice 8
choice 9
end{choice}

end{questions}
end{document}

First, I checked whether this package was installed on my system:

✗ sudo tlmgr install exam    
Password:
tlmgr: package repository https://mirrors.concertpass.com/tex-archive/systems/texlive/tlnet (verified)
tlmgr install: package already present: exam

When I pdflatex against the above file, I hit an error with exam.sty not found:

✗ pdflatex easy_questions.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020) (preloaded format=pdflatex)
 restricted write18 enabled.
entering extended mode
(./easy_questions.tex
LaTeX2e <2020-02-02> patch level 5
L3 programming layer <2020-03-06>
(/usr/local/texlive/2020/texmf-dist/tex/latex/base/article.cls
Document Class: article 2019/12/20 v1.4l Standard LaTeX document class
(/usr/local/texlive/2020/texmf-dist/tex/latex/base/size10.clo))

! LaTeX Error: File `exam.sty' not found.

Type X to quit or <RETURN> to proceed,
or enter new name. (Default extension: sty)

Does this mean that the package is not installed? I downloaded exam.sty from https://stuff.mit.edu/afs/athena/contrib/tex-contrib/Macros/exam.sty and copied it into the same directory as my latex source. Now I get another error about art11.sty not found:

✗ pdflatex easy_questions.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.21 (TeX Live 2020) (preloaded format=pdflatex)
 restricted write18 enabled.
entering extended mode
(./easy_questions.tex
LaTeX2e <2020-02-02> patch level 5
L3 programming layer <2020-03-06>
(/usr/local/texlive/2020/texmf-dist/tex/latex/base/article.cls
Document Class: article 2019/12/20 v1.4l Standard LaTeX document class
(/usr/local/texlive/2020/texmf-dist/tex/latex/base/size10.clo)) (./exam.sty

! LaTeX Error: File `art11.sty' not found.

Type X to quit or <RETURN> to proceed,
or enter new name. (Default extension: sty)

Enter file name: 

How can I fix these errors? I thought it would be pretty straight-forward to install this package.