Cut a 4-meter-long cuboid into two pieces, and the surface area increases by 100cm**2. What is the volume of this piece of wood in decimeters**3.
把一个长4米的长方体木料切成两段，表面积增加了100cm**2，这根木料的体积是多少分米**3．
<gadget id="calculator">100 / 2</gadget>
<output>50</output>

<gadget id="calculator">100 / 1_000</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">50 * 4 * (1/10)</gadget>
<output>20</output>

<result>20</result>