Add 40 to the numerator of (5/8), how much should be added to the denominator to keep the size of the fraction constant
(5/8)的分子加上40，要使分数的大小不变，分母应加上多少
<gadget id="calculator">8 * 9</gadget>
<output>72</output>

<gadget id="calculator">72 - 8</gadget>
<output>64</output>

<result>64</result>