Xinxing Farm cultivates fruit saplings in a piece of land. (1/4) of this field is planted with peach trees, (2/5) with pear trees, and the rest are planted with apple trees. What fraction of the land are apple trees?
新星农场在一块地里培育果树苗．这块地的(1/4)栽桃树，(2/5)栽梨树，其余的栽苹果树．苹果树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">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (1/4) - (2/5)</gadget>
<output>7/20 = around 0.35</output>

<result>7/20 = around 0.35</result>