Xiaofang has 100 candies, and the number after eating is exactly 9 times that of 9.
小芳有100颗糖，吃掉多少后正好是9的9倍．
<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">100 - 81</gadget>
<output>19</output>

<result>19</result>