There is a wall clock that strikes once every hour, and how many times it strikes at what time. The clock strikes 5 times, and it takes 4 seconds to finish the bell, and the clock strikes 10 times, how many seconds to finish the bell.
有一个挂钟，每小时敲一次钟，几点钟敲几下．钟敲5下，4秒钟敲完，钟敲10下，多少秒钟敲完．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 / 4</gadget>
<output>1</output>

<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">1 * 9</gadget>
<output>9</output>

<result>9</result>