Two gears mesh with each other. The large gear has 36 teeth and the small gear has 27 teeth. When the large gear makes 3 revolutions, how many revolutions does the small gear make? (Answer with the knowledge of proportion)
两个相互咬合的齿轮，大齿轮有36个齿，小齿轮有27个齿，当大齿轮转3圈时，小齿轮转几圈？(用比例的知识解答)
<gadget id="calculator">36 * 3</gadget>
<output>108</output>

<gadget id="calculator">108 / 27</gadget>
<output>4</output>

<result>4</result>