Lele read "One Hundred Thousand Whys", read 25% of the whole book on the first day, and (2/5) of the whole book on the second day, leaving 70 pages unread. How many pages does this book have?
乐乐看《十万个为什么》，第一天看了全书的25%，第二天看了全书的(2/5)，还剩70页没看．这本书共有多少页？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

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

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

<result>200</result>