A 4-meter-long log is sawed into 4 sections, and the surface area is increased by 30 square decimeters. What is the original volume of this log?
把一根4米长圆木锯成4段，表面积比原来增加了30平方分米，这根圆木原来体积是多少立方分米？
<gadget id="calculator">30 / 6</gadget>
<output>5</output>

<gadget id="calculator">4 * 10</gadget>
<output>40</output>

<gadget id="calculator">5 * 40</gadget>
<output>200</output>

<result>200</result>