In a piece of land, (1/4) is planted with roses, (2/5) is planted with tulips, and the rest is planted with rhododendrons. What percentage of the total area is the area planted with rhododendrons?
一块地，其中的(1/4)种玫瑰花，(2/5)种郁金香，其余的部分种杜鹃花．种杜鹃花的面积占总面积的几分之几？
<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">(1/4) + (2/5)</gadget>
<output>13/20 = around 0.65</output>

<gadget id="calculator">1 - (13/20)</gadget>
<output>7/20 = around 0.35</output>

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