A log 10 meters long should be divided into 5 equal parts. It takes 4 minutes to saw the next section. How many minutes will it take in total.
一根木头长10米要把它平均分成5段．每锯下一段需要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>