What is the minimum angle between the hour and minute hands of a wall clock at 4 o'clock?
一只挂钟，在4时整的时候，时针与分针的最小夹角是多少度．
<gadget id="calculator">360 / 12</gadget>
<output>30</output>

<gadget id="calculator">30 * 4</gadget>
<output>120</output>

<result>120</result>