Reading a book, I read (1/4) of the whole book on the first day, and read 120 pages on the second day. At this time, the ratio of the number of pages I have read to the number of pages I have not read is 2:3. How many pages does this book have? (Hint: You can find the unit 1<the number of pages of this book> by only asking for a fraction of 120.)
看一本书，第一天看了全书的(1/4)，第二天看了120页，这时已看与未看页数的比是2：3，这本书有多少页？(提示：只要求出120占几分之几就可以求单位1＜这本书的页数＞)
<gadget id="calculator">2 + 3</gadget>
<output>5</output>

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

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

<gadget id="calculator">(2/5) - (1/4)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">120 / (3/20)</gadget>
<output>800</output>

<result>800</result>