There are two gears, large and small, which intersect with each other. The large gear has 90 teeth, and the small gear has 18 teeth. If the large gear rotates 100 revolutions per minute, how many revolutions does the small gear rotate per minute? (Answer with proportional knowledge)
有大小两个互交合的齿轮，大齿轮有90个齿，小齿轮有18个齿；如果大齿轮每分钟转100转，小齿轮每分钟转多少转？(用比例知识解答)
<gadget id="calculator">90 * 100</gadget>
<output>9_000</output>

<gadget id="calculator">9_000 / 18</gadget>
<output>500</output>

<result>500</result>