How many degrees does the hour hand rotate around the center of the clock face to go from 3:00 to 9:00.
时针绕钟面中心旋转多少°度，才能从3：00走到9：00．
<gadget id="calculator">360 / 60</gadget>
<output>6</output>

<gadget id="calculator">6 * 30</gadget>
<output>180</output>

<result>180</result>