If a rectangle is 2 cm long and 1.5 cm wide, what is the perimeter in cm?
一个长方形的长2厘米，宽1.5厘米，周长是多少厘米．
<gadget id="calculator">2 + 1.5</gadget>
<output>3.5</output>

<gadget id="calculator">2 * 3.5</gadget>
<output>7</output>

<result>7</result>