<<< native
[ EFraction
    NormalFrac
    (ENumber "4")
    (EGrouped
       [ ENumber "2"
       , ESymbol Bin "+"
       , EFraction
           NormalFrac
           (ENumber "3")
           (EGrouped
              [ ENumber "1"
              , ESymbol Bin "+"
              , EFraction NormalFrac (ENumber "1") (ENumber "2")
              ])
       ])
, ESymbol Rel "="
, EFraction
    NormalFrac
    (EGrouped
       [ ENumber "1"
       , ESymbol Bin "+"
       , EFraction
           NormalFrac
           (ENumber "9")
           (EGrouped
              [ ENumber "2"
              , ESymbol Bin "+"
              , EFraction NormalFrac (ENumber "1") (ENumber "4")
              ])
       ])
    (ENumber "5")
]
>>> tex
\frac{4}{2 + \frac{3}{1 + \frac{1}{2}}} = \frac{1 + \frac{9}{2 + \frac{1}{4}}}{5}