[Bug] 分数模式下的运算Bug
>> 25^(-2)+35^(-2)+75^(-2)+100^(-2)+175^(-2)
in> 25^(-2)+35^(-2)+75^(-2)+100^(-2)+175^(-2)
out> (175*100*75*35*^2*^2*^2*^2+175*100*75*25*^2*^2*^2*^2+175*100*875*^2*^2*^2*^2+175*75*875*^2*^2*^2*^2+100*75*875*^2*^2*^2*^2)|175*100*75*875*^2*^2*^2*^2*^2
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