Mingming bought a copy of "Andersen's Fairy Tales", he read (1/5) of this book on the first day, and (1/4) of this book on the second day. How much of this book is left unread?
明明买了一本《安徒生童话》，他第一天看了这本书的(1/5)，第二天看了这本书的(1/4)．还剩这本书的几分之几没有看？
<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 - (1/5) - (1/4)</gadget>
<output>11/20 = around 0.55</output>

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