The perimeter of the rectangular tabletop is 56 decimeters, the length is 18 decimeters, what is the width
长方形桌面的周长是56分米，长是18分米，宽是多少
<gadget id="calculator">56 / 2</gadget>
<output>28</output>

<gadget id="calculator">28 - 18</gadget>
<output>10</output>

<result>10</result>