Junjun read a book, he read 20 pages on the first day, which was 1/4 more than the second day, and he read the whole book on the second day (1/9). How many pages does this book have?
军军读一本书，第一天读了20页，比第二天多读了(1/4)，第二天读的是全书的(1/9)．这本书共有多少页？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 + (1/4)</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">1 / 9</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">20 / (5/4) / (1/9)</gadget>
<output>144</output>

<result>144</result>