pair of large and small gears mesh with each other. The large gear has 40 teeth and rotates at 450 revolutions per minute. If the small gear rotates at 500 revolutions per minute, how many teeth should the small gear have?
一对互相咬合的大小齿轮，其中大齿轮有40个齿，每分钟转450转，要使小齿轮每分钟转500转，小齿轮应有多少个齿？
<gadget id="calculator">450 * 40</gadget>
<output>18_000</output>

<gadget id="calculator">18_000 / 500</gadget>
<output>36</output>

<result>36</result>