The perimeter of a rectangle is 16 cm, the length of the rectangle is 5 cm, and the width in cm.
一个长方形的周长是16厘米，这个长方形的长是5厘米，宽是多少厘米．
<gadget id="calculator">2 * 5</gadget>
<output>10</output>

<gadget id="calculator">16 - 10</gadget>
<output>6</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<result>3</result>