If three squares with side lengths of 1 decimeter are used to form a rectangle, what is the perimeter of the rectangle?
如果用三个边长是1分米的正方形拼成一个长方形，那么这个长方形的周长是多少分米．
<gadget id="calculator">1 * 3</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>