Xiaohong reads a book, read 80 pages in the first week, read (1/2) of this book in the second week, and left (1/3) of this book without reading. How many pages does this book have?
小红读一本书，第一周读了80页，第二周读了这本书的(1/2)，还剩这本书的(1/3)没有读．这本书有多少页？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/2) - (1/3)</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">80 / (1/6)</gadget>
<output>480</output>

<result>480</result>