book is read (2/5) on the first day, 25% of the book is read on the second day, and there are 70 pages left. How many pages are there in this book?
一本书，第一天读了(2/5)，第二天读了全书的25%，还剩70页没读，这本书一共有多少页？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 / 100</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">70 / (7/20)</gadget>
<output>200</output>

<result>200</result>