It takes Xiaojun 9 seconds to go up each floor. According to this calculation, how many seconds does it take him to go from the first floor to the fifth floor.
小军每上一层楼需要9秒，照这样计算，他从一楼上到五楼需要多少秒钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 9</gadget>
<output>36</output>

<result>36</result>