I have already read a book (2/5), which is exactly 80 pages. How many pages does this book have?
已经看了一本书的(2/5)，正好是80页．这本书有多少页？
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">80 / (2/5)</gadget>
<output>200</output>

<result>200</result>