It takes half a minute to go up a flight of stairs, so how many minutes does it take from 1 floor to 5 floors?
每上一层楼梯用半分钟，那么1层到5层楼共用多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">0.5 * 4</gadget>
<output>2</output>

<result>2</result>