There is a steel pipe that needs to be sawed into 5 sections. It takes 3 minutes to saw each section, and how many minutes will it take to saw all of them.
有一根钢管要锯成5段，每锯开一处要花3分钟，全部锯完要多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<result>12</result>