Xiaohong reads a story book. She reads (2/5) of the whole book every day, (1/4) of the whole book on the second day, and reads the whole book on the third day. How much of the book did you read less on the first day?
小红看一本故事书，每一天看了全书的(2/5)，第二天看了全书的(1/4)，第三天将这本书全看完，问：第三天比第一天少看全书的几分之几？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">(2/5) - (7/20)</gadget>
<output>1/20 = around 0.05</output>

<result>1/20 = around 0.05</result>