The melon seed store buys (5/4) tons of melon seeds, the first wholesale (1/5) of the total, and the second wholesale (1/4) of the total. What percentage of the total amount is left that has not been wholesaled?
瓜子店新进(5/4)吨瓜子，第一次批发出总数的(1/5)，第二次批发出总数的(1/4)．还剩总数的几分之几没有批发出去？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

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

<gadget id="calculator">(1/5) + (1/4)</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">1 - (9/20)</gadget>
<output>11/20 = around 0.55</output>

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