The area of a circular flowerbed is (4/5) hectare, and 3 different kinds of flowers are planted in it. Among them, peonies account for (2/5) of the total area, lilies account for (1/20) of the total area, and the rest are roses. What percentage of the total area do roses occupy?
一个圆形花圃的面积是(4/5)公顷，里面种了3种不同的花．其中牡丹占总面积的(2/5)，百合占总面积的(1/20)，其余是玫瑰．玫瑰占总面积的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 / 20</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 - (2/5) - (1/20)</gadget>
<output>11/20 = around 0.55</output>

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