Add a certain number to the numerator of (17/55), and subtract the same number from the denominator. After the fraction is reduced, it becomes (3/5). What is the certain number?
给(17/55)的分子加上某数，分母减去同一个数，分数的约分后变为(3/5)，某数是多少．
<gadget id="calculator">17 + 55</gadget>
<output>72</output>

<gadget id="calculator">3 + 5</gadget>
<output>8</output>

<gadget id="calculator">72 / 8</gadget>
<output>9</output>

<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">27 - 17</gadget>
<output>10</output>

<result>10</result>