The area of a piece of land is 20 hectares, of which (1/4) is planted with corn, (1/5) is planted with potatoes, and the rest is planted with tomatoes. What percentage of the area is planted with tomatoes?
一块地的面积是20公顷，其中的(1/4)种玉米，(1/5)种土豆，剩下的部分种西红柿，种西红柿的面积占这块地的几分之几？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">1 - (1/4) - (1/5)</gadget>
<output>11/20 = around 0.55</output>

<result>11/20 = around 0.55</result>