A math book is 5 millimeters thick, so how many math books are exactly 1 decimeter when piled up.
一本数学书厚5毫米，那么多少本数学书垒起来刚好是1分米．
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">1 * 20</gadget>
<output>20</output>

<result>20</result>