Xiao Ming bought an extra-curricular book with a total of 200 pages. He read (1/5) of the whole book on the first day and the rest (1/4) on the second day. Which page should Xiao Ming start reading on the third day?
小明买了一本共200页的课外书，他第一天读了全书的(1/5)，第二天读了余下的(1/4)，第三天小明应从哪页读起呢？
<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">200 - 40</gadget>
<output>160</output>

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

<gadget id="calculator">160 * (1/4)</gadget>
<output>40</output>

<gadget id="calculator">40 + 40 + 1</gadget>
<output>81</output>

<result>81</result>