If a cylinder with a height of 2m is sawn into two pieces, the surface area is increased by 20m**2, what is the original volume of the cylinder?
把高2m圆柱锯成两段，表面积增加了20m**2，原来这个圆柱的体积是多少．
<gadget id="calculator">20 / 2</gadget>
<output>10</output>

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

<result>20</result>