\magnification\magstep1
\baselineskip 14pt
\font\tenrm="Junicode:mapping=tex-text" at 12pt
% set up Cambria Math as math roman, symbol and extension families
\font\1="Cambria Math:script=math" at 10pt
\font\2="Cambria Math:script=math;+ssty=0'' at 7pt
\font\3="Cambria Math:script=math;+ssty=1'' at 5pt
\textfont0=\1 \scriptfont0=\2 \scriptscriptfont0=\3
\textfont2=\1 \scriptfont2=\2 \scriptscriptfont2=\3
\textfont3=\1 \scriptfont3=\2 \scriptscriptfont3=\3


% use Cambria Math with italic mapping for family 1
\font\4="Cambria Math:script=math;mapping=math-italic" at 10pt
\font\5="Cambria Math:script=math;mapping=math-italic;+ssty=0" at 7pt
\font\6="Cambria Math:script=math;mapping=math-italic;+ssty=1" at 5pt
\textfont1=\4 \scriptfont1=\5 \scriptscriptfont1=\6



\XeTeXmathcode`\-="2 "2 "2212 % minus sign
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\XeTeXmathchardef\pi="7 "1 `π
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$(x+y)^2=x^2+2xy+y^2$

\end