If a 2-meter-long square log (with a square bottom) is sawed into three pieces, the surface area increases by 5.6 square decimeters. What is the original volume of this square log?
把一根长2米的方木(底面是正方形)锯成三段，表面积增加5.6平方分米，原来这根方木的体积是多少立方分米？
<gadget id="calculator">5.6 / 4</gadget>
<output>1.4</output>

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

<gadget id="calculator">1.4 * 20</gadget>
<output>28</output>

<result>28</result>