A fraction, if you increase its denominator by 1, you get (1/3), if you decrease its denominator by 1, you get (2/5), what is the original fraction
一个分数，如果把它的分母增加1就得到(1/3)，如果把它的分母减少1就得到(2/5)，这个分数原来是多少
<gadget id="calculator">4 / 11</gadget>
<output>4/11 = around 0.363636</output>

<result>4/11 = around 0.363636</result>