A building has 9 floors. It takes Xiao Ming 2 minutes to go up each floor. How many minutes does it take to go up to the 9th floor?
一幢楼有9层，小明每上一层需要2分钟，上到9层一共要花多少分钟．
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>