Xiaomin reads a book, 50 pages on the first day, (1/6) of the whole book on the second day, and (4/9) of the whole book in two days. How many pages does this book have?
小敏看一本书，第一天看了50页，第二天看了全书的(1/6)，两天共看了全书的(4/9)，这本书共有多少页？
<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(4/9) - (1/6)</gadget>
<output>5/18 = around 0.277778</output>

<gadget id="calculator">50 / (5/18)</gadget>
<output>180</output>

<result>180</result>