For a true fraction, the sum of the numerator and the denominator is 27. For example, the numerator is subtracted by 2, and the denominator is increased by 1. After reduction, it is (3/10). What is the original fraction?
一个真分数，分子和分母的和是27，如分子减2，分母增加1，约简后是(3/10)，原分数是多少．
<gadget id="calculator">6 + 2</gadget>
<output>8</output>

<gadget id="calculator">20 - 1</gadget>
<output>19</output>

<gadget id="calculator">8 / 19</gadget>
<output>8/19 = around 0.421053</output>

<result>8/19 = around 0.421053</result>