The watch is 30 seconds faster than the clock per hour, and the clock is 30 seconds slower than standard time per hour. Ask if the watch is fast or slow? How many seconds is the difference between day and night?
表比钟每小时快30秒，钟每小时比标准时慢30秒．问表是快还是慢？一昼夜相差多少秒？
<gadget id="calculator">30 * 24</gadget>
<output>720</output>

<gadget id="calculator">24 - 0.2</gadget>
<output>23.8</output>

<gadget id="calculator">30 * 23.8</gadget>
<output>714</output>

<gadget id="calculator">720 - 714</gadget>
<output>6</output>

<result>6</result>