The area of a rectangular land is 15 hectares. Use (1/3) of this land to plant wheat and (1/5) to plant cotton. How many hectares more wheat is planted than cotton?
一块长方形地的面积是15公顷，用这块地的(1/3)种植小麦，(1/5)种植棉花，小麦比棉花多种植多少公顷？
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/3) - (1/5)</gadget>
<output>2/15 = around 0.133333</output>

<gadget id="calculator">15 * (2/15)</gadget>
<output>2</output>

<result>2</result>