A piece of paper has an area of 90 square centimeters, a width of 6 centimeters, and a length of centimeters.
一张纸的面积是90平方厘米，宽是6厘米，长是多少厘米．
<gadget id="calculator">90 / 6</gadget>
<output>15</output>

<result>15</result>