What is the surface area of a cube whose sum of sides is 60 cm?
棱长之和是60cm的正方体，它的表面积是多少．
<gadget id="calculator">72 / 12</gadget>
<output>6</output>

<gadget id="calculator">6 * 6 * 6</gadget>
<output>216</output>

<result>216</result>