The length of a rectangle is 8 cm and the width is 3 cm less than the length. What is the perimeter of the rectangle?
一个长方形的长8cm，宽比长少3cm，这个长方形的周长是多少．
<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<result>26</result>