Smiling and reading an 80-page extra-curricular book, (1/4) read this book on the first day, and (2/5) read this book on the second day. What fraction of the book did she read in two days?
笑笑看一本80页课外书，第一天看了这本书的(1/4)，第二天看了这本书的(2/5)．她两天共看这本书的几分之几？
<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>

<result>13/20 = around 0.65</result>