The clock on the green square will ring whenever the hour is on, and it will ring a few times. It takes 20 seconds at five o'clock, and how many seconds does it take to ring the bell at twelve o'clock?
绿化广场上的时钟，每当整点的时候都会敲响，几点就敲几下．五点的时候共用时20秒，十二时的时候，敲钟共要用时多少秒？
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<gadget id="calculator">5 * 11</gadget>
<output>55</output>

<result>55</result>