cancel.test

<<< native
[ EBoxed
    (EGrouped
       [ ECancel ForwardSlash (EIdentifier "x")
       , ESymbol Bin "+"
       , ECancel BackSlash (EIdentifier "y")
       , ESymbol Rel "="
       , ECancel XSlash (EIdentifier "z")
       ])
]
>>> starmath
\boxed{\cancel{x} + \bcancel{y} = \xcancel{z}}