If the perimeter of a rectangle is 16 cm and the width is 3 cm, what is the length in cm?
一个长方形的周长是16厘米，宽是3厘米，长应为多少厘米．
<gadget id="calculator">16 / 2</gadget>
<output>8</output>

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

<result>5</result>