There is a fraction, adding 1 to the denominator is (2/5), and subtracting 2 from the denominator is (4/9), what is the fraction?
有一个分数，分母加上1，则为(2/5)，分母减去2为(4/9)，这个分数是多少．
<gadget id="calculator">12 / 29</gadget>
<output>12/29 = around 0.413793</output>

<result>12/29 = around 0.413793</result>