After reading (1/3) of a book, exactly 150 pages have been read. How many pages are there in this book?
一本书，读完它的(1/3)，正好读了150页，这本书一共多少页．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">150 / (1/3)</gadget>
<output>450</output>

<result>450</result>