What is the volume of a cuboid 2 meters long, whose cross-section is a square with side length 5 decimeters?
一根长2米的长方体木料，横截面是边长为5分米的正方形，它的体积是多少．
<gadget id="calculator">2 * 10</gadget>
<output>20</output>

<gadget id="calculator">5 * 5 * 20</gadget>
<output>500</output>

<result>500</result>