A piece of wood is 5 meters long, if it is sawed into 5 sections, and it takes 5 minutes to saw the next section, how many minutes will it take to finish sawing the piece of wood?
一根木头长5米，把它锯成5段，锯下一段要5分钟，锯完这根木头要用多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<result>20</result>