If the base of a cuboid is a square with side length 8 cm and height 5 cm, what is the sum of its sides in cm?
一个长方体的底面是边长为8厘米的正方形，高5厘米，它的棱长之和是多少厘米．
<gadget id="calculator">8 + 8 + 5</gadget>
<output>21</output>

<gadget id="calculator">21 * 4</gadget>
<output>84</output>

<result>84</result>