A log with a length of 2 meters is sawn into 5 sections on average, and the surface area is increased by 40 square decimeters compared with the original one. Find the volume of each section of the log.
一根圆木长2米，平均锯成5段，表面积比原来增加40平方分米，求每段圆木的体积．
<gadget id="calculator">40 / 8</gadget>
<output>5</output>

<gadget id="calculator">2 * 10</gadget>
<output>20</output>

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

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

<result>20</result>