What is the perimeter in centimeters when three small squares with sides of 1 cm are put together to form a large rectangle?
三个边长都是1厘米的小正方形拼成大长方形后，周长是多少厘米．
<gadget id="calculator">3 * 1</gadget>
<output>3</output>

<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">4 * 2</gadget>
<output>8</output>

<result>8</result>