If 4 squares with side lengths of 1 cm are used to form a rectangle, what is the perimeter of the rectangle in cm?
用4个边长为1厘米的正方形拼成一个长方形，这个长方形的周长是多少厘米．
<gadget id="calculator">4 * 1</gadget>
<output>4</output>

<gadget id="calculator">4 + 1</gadget>
<output>5</output>

<gadget id="calculator">5 * 2</gadget>
<output>10</output>

<result>10</result>