fraction, the numerator plus the denominator is equal to 168; the numerator and the denominator are both subtracted by 6, and the fraction becomes (5/7), what is the original fraction.
一个分数，分子加分母等于168；分子、分母都减去6，分数变成(5/7)，原来的分数是多少．
<gadget id="calculator">168 - 12</gadget>
<output>156</output>

<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">5 / 12</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">156 * (5/12)</gadget>
<output>65</output>

<gadget id="calculator">65 + 6</gadget>
<output>71</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">156 * (7/12)</gadget>
<output>91</output>

<gadget id="calculator">91 + 6</gadget>
<output>97</output>

<gadget id="calculator">71 / 97</gadget>
<output>71/97 = around 0.731959</output>

<result>71/97 = around 0.731959</result>