There are two pulleys connected together. The diameter of the big pulley is 2 meters, and the diameter of the small pulley is 0.5 meters. If the big pulley makes one revolution, how many turns does the small pulley make?
有两个连在一起的皮带轮，大轮直径2米，小轮直径0.5米，若大轮转一圈，小轮转几圈？
<gadget id="calculator">3.14 * 2</gadget>
<output>6.28</output>

<gadget id="calculator">3.14 * 0.5</gadget>
<output>1.57</output>

<gadget id="calculator">6.28 / 1.57</gadget>
<output>4</output>

<result>4</result>