A bus leaves every 20 minutes from the bus station. Counting from the first car, how many cars are driven in 1 hour.
公交汽车站每隔20分钟就开出一辆车．从第一辆车开出算起，1小时共开出多少辆车．
<gadget id="calculator">60 / 20</gadget>
<output>3</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<result>4</result>