A book, I have read (3/5) of this book, and there are 150 pages left, how many pages does this book have?
一本书，已经看了这本书的(3/5)，还剩下150页，这本书共有多少页？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">150 / (2/5)</gadget>
<output>375</output>

<result>375</result>