What is the perimeter of a rectangle that is 5 cm long and 3 cm wide?
长5厘米，宽3厘米的长方形的周长是多少厘米．
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>