Xiaohong has a story book. She read (1/5) of the whole book on the first day, (1/4) of the whole book on the second day, and half of the total number she read on the third day. How much of this book did you read in three days?
小红有一本故事书，她第一天看了全书的(1/5)，第二天看了全书的(1/4)，第三天看的是前两天看的总数的一半，第三天看了这本书的几分之几？
<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">(9/20) / 2</gadget>
<output>9/40 = around 0.225</output>

<result>9/40 = around 0.225</result>