A true fraction, after multiplying its numerator and denominator by 3 times, the sum of numerator and denominator is 12, what is the original fraction.
一个真分数，把它的分子和分母都扩大3倍后，分子和分母的和是12，这个分数原来是多少．
<gadget id="calculator">3 / 9</gadget>
<output>1/3 = around 0.333333</output>

<result>1/3 = around 0.333333</result>