An orchard covers an area of 20 hectares, of which (2/5) is planted with apple trees, (1/4) is planted with pear trees, and the rest is planted with oranges, how many hectares are planted with oranges?
一个果园占地20公顷，其中的(2/5)种苹果树，(1/4)种梨树，剩下的地种橘子，种橘子多少公顷？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

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

<gadget id="calculator">20 * (7/20)</gadget>
<output>7</output>

<result>7</result>