There are two rectangles with a length of 4 cm and a width of 2 cm. Put them together to form a rectangle. What is the perimeter of the rectangle in centimeters?
有两个长方形，长都是4厘米，宽都是2厘米，把它们拼成一个长方形，这个长方形的周长是多少厘米厘米．
<gadget id="calculator">4 + 4 + 2</gadget>
<output>10</output>

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

<result>20</result>