A piece of wood is 6 meters long and must be sawed into 4 sections. It takes 5 minutes to saw each segment, how many minutes will it take to complete the saw.
一根木头长6米，要把它锯成4段．每锯一段需要5分钟，锯完一共需要多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>