A rectangular piece of glass has an area of 15 square decimeters, a length of 5 decimeters, and a width of 5 decimeters.
一块长方形玻璃面积是15平方分米，长是5分米，宽是多少．
<gadget id="calculator">15 / 5</gadget>
<output>3</output>

<result>3</result>