Wang Gang is reading a book. He has read 3 pages less than 40% of the total number of pages in the book, leaving 75 pages unread. How many pages are there in this book?
王刚看一本书，已看过的比全书总页数的40%少3页，还剩下75页没看，这本书共有多少页？
<gadget id="calculator">75 - 3</gadget>
<output>72</output>

<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 - (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">72 / (3/5)</gadget>
<output>120</output>

<result>120</result>