A piece of wood is 15 meters long, and it is sawed into 3-meter-long sections. It takes 5 minutes to saw each section. How many minutes does it take to complete the sawing?
一根木料长15米，把它锯成3米长一段，每锯一段要5分钟，锯完共用了多少分钟．
<gadget id="calculator">15 / 3</gadget>
<output>5</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<result>20</result>