A piece of land, in which (1/5) is planted with corn, (1/6) is planted with vegetables, and the rest are planted with watermelons. What percentage of the land is planted with watermelons?
一块地，其中(1/5)种玉米，(1/6)种青菜，其余种西瓜．种西瓜的面积占这块地的几分之几？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">1 - (1/5) - (1/6)</gadget>
<output>19/30 = around 0.633333</output>

<result>19/30 = around 0.633333</result>