A rectangle has a perimeter of 34 meters and a width of 7 meters. What is the length in meters?
一个长方形，它的周长是34米，宽是7米，长是多少米．
<gadget id="calculator">34 / 2</gadget>
<output>17</output>

<gadget id="calculator">17 - 7</gadget>
<output>10</output>

<result>10</result>