If the perimeter of a rectangle is 16 cm and its width is 3 cm, what is its length?
一个长方形的周长是16厘米，其中它的宽是3厘米，长是多少厘米？
<gadget id="calculator">16 / 2</gadget>
<output>8</output>

<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<result>5</result>