A steel pipe is 20 meters long. Now it is sawed into 5 sections on average. It takes 5 minutes on average to saw each section. How many minutes will it take to complete the sawing?
一根钢管长20米，现将它平均锯成5段，每锯一段平均需要5分钟，锯完一共需要多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<result>20</result>