Xiao Ming goes upstairs, and it takes 20 seconds for each floor to go up, so how many seconds does it take to go from the 1st floor to the 5th floor at this speed?
小明上楼，每上一层楼需要20秒，那么以这样的速度，从1楼到5楼需要多少秒．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 20</gadget>
<output>80</output>

<result>80</result>