A book with 200 pages, read (1/5) of the whole book on the first day, (1/4) of the whole book on the second day, and from which page should I read it on the third day?
一本书200页，第一天读了全书的(1/5)，第二天读了全书的(1/4)，第三天从第几页看起？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">200 * (1/5)</gadget>
<output>40</output>

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

<gadget id="calculator">200 * (1/4)</gadget>
<output>50</output>

<gadget id="calculator">40 + 50 + 1</gadget>
<output>91</output>

<result>91</result>