A square log is 10 meters long, and it needs to be divided into 5 sections on average. It takes 9 minutes to saw each section. How many minutes will it take to finish sawing.
一根方木长10米，要把它平均分成5段，每锯下一段需要9分钟，锯完要花多少分钟．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<result>36</result>