Multiply: \ac23\ot\acxy\ac{2}{3} \ot \ac{x}{y}\ac23\ot\acxy.
\ac2x3y\ac{2x}{3y}\ac2x3y
\ac2y3x\ac{2y}{3x}\ac2y3x
\ac2+x3+y\ac{2+x}{3+y}\ac2+x3+y
\ac6xy\ac{6}{xy}\ac6xy