Use 4 small sticks with a length of 2 cm and 4 sticks with a length of 5 cm to build a largest square. What is the perimeter of this square in cm?
用4根长2厘米和4根长5厘米的小棒搭出一个最大的正方形，这个正方形的周长是多少厘米．
<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<gadget id="calculator">4 * 5</gadget>
<output>20</output>

<gadget id="calculator">8 + 20</gadget>
<output>28</output>

<result>28</result>