The hour hand of the clock goes from pointing 3 to pointing 6, how many degrees does the hour hand rotate around the center of the clock.
钟表的时针从指向3到指向6，时针绕钟表的中心旋转了多少度．
<gadget id="calculator">360 / 12</gadget>
<output>30</output>

<gadget id="calculator">30 * 3</gadget>
<output>90</output>

<result>90</result>