Fold a square of paper with a side length of 6 cm into two rectangles. What is the perimeter of each rectangle?
把一个边长为6厘米的正方形的纸，对折成两个长方形，每个长方形的周长是多少．
<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">6 + 3</gadget>
<output>9</output>

<gadget id="calculator">9 * 2</gadget>
<output>18</output>

<result>18</result>