simple_sum_formula.test

<<< tex
\sum_{i=1}^100 x = \frac{100*101}{2}

>>> native
[ EUnderover
    True
    (ESymbol Op "\8721")
    (EGrouped [ EIdentifier "i" , ESymbol Rel "=" , ENumber "1" ])
    (ENumber "100")
, EIdentifier "x"
, ESymbol Rel "="
, EFraction
    NormalFrac
    (EGrouped [ ENumber "100" , ESymbol Bin "*" , ENumber "101" ])
    (ENumber "2")
]