What is the perimeter of a rectangle made of 3 small squares with side lengths of 1 cm?
用3个边长是1厘米的小方块分别拼成长方形，它的周长是多少．
<gadget id="calculator">1 + 1 + 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>