A cuboid block of wood can be cut into two identical small cubes of wood. After being cut into two small cubes, the sum of the lengths of the edges of the two small cubes is 20 cm longer than the sum of the lengths of the edges of the original cuboid. What is the volume of the original cuboid? centimeter.
一个长方体木块可以截成两个完全一样的小正方体木块，截成两个小正方体后，两个小正方体的棱长总和比原长方体棱长总和增加20厘米，原来长方体的体积是多少立方厘米．
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">20 / 8</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">(5/2) * 2</gadget>
<output>5</output>

<gadget id="calculator">(5/2) * (5/2) * 5</gadget>
<output>125/4 = around 31.25</output>

<result>125/4 = around 31.25</result>