How many degrees did the hour hand turn from 12 o'clock to 4 o'clock?
时针从12点走到4点，转动了多少度．
<gadget id="calculator">360 / 12</gadget>
<output>30</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

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

<result>120</result>