Xiao Ming reads a 200-page story book. He reads (1/5) of the whole book on the first day and (1/4) of the whole book on the second day. From what number in the book should I read the third day?
小明看一本200页的故事书，第一天看了全书的(1/5)，第二天看了全书的(1/4)．第三天应从全书的第几也看起？
<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">200 * (9/20)</gadget>
<output>90</output>

<gadget id="calculator">90 + 1</gadget>
<output>91</output>

<result>91</result>