A piece of wood is sawn into 5 sections on average, and each section takes 4 minutes to saw. How many minutes will it take to complete the sawing?
一根木头平均锯成5段，每锯下一段要4分钟，锯完一共要花多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<result>16</result>