COMMENT ⊗   VALID 00004 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	%\read16 to\pagenumber
C00003 00003	\dangerexercise Typeset the display\ \lower12pt\null
C00005 00004	% now we print the answers, if any
C00006 ENDMK
C⊗;
%\read16 to\pagenumber
\input manmac
\tenpoint
\pageno=800
%\pageno=\pagenumber
\def\rhead{Experimental Pages for The \TeX book}
\def\chapno{ X}
{\catcode`\%=12 \immediate\write\ans{% Answers for galley proofs:}}
\dangerexercise Typeset the display\ \lower12pt\null
$\tenpoint\smash{\displaystyle
\left\lgroup\matrix{a&b&c\cr d&e&f\cr}\right\rgroup
  \left\lgroup\matrix{u&x\cr v&y\cr w&z\cr}\right\rgroup
},$ \ using ↑|\lgroup| and ↑|\rgroup|.

\bye
\dangerexercise Use ↑|\lgroup| and ↑|\rgroup| to typeset\ \lower12pt\null
$\tenpoint\smash{\displaystyle
\left\lgroup\matrix{a&b&c\cr d&e&f\cr}\right\rgroup
  \left\lgroup\matrix{u&x\cr v&y\cr w&z\cr}\right\rgroup
}.$

\bye
% now we print the answers, if any

% that blank line will stop an unfinished \answer
\immediate\closeout\ans
\vfill\eject
\ninepoint
\input answers
\bye