If it takes 9 minutes to saw a cylindrical piece of wood into 4 sections on average, how many minutes will it take to saw it into 5 sections?
把一个圆柱形木料平均锯成4段，用了9分钟，锯成5段需要用多少分钟．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">9 / 3</gadget>
<output>3</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">3 * 4</gadget>
<output>12</output>

<result>12</result>