Wang Lin is reading a storybook, and he has read 60% of the book, leaving 120 pages unread. How many pages are there in this book?
王林读一本故事书，已经读了全书的60%，还剩120页没读，这本书共有多少页？
<gadget id="calculator">60 / 100</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">120 / (2/5)</gadget>
<output>300</output>

<result>300</result>