Xiao Ming read a story book, 40% of it in the first week, 25% of the whole book in the second week, and just finished reading 175 pages. How many pages are there in total?
小明看了一本故事书，第一周看了40%，第二周看了全书的25%，再看175页刚好看完，这本书一共是多少页？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (2/5) - (1/4)</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">175 / (7/20)</gadget>
<output>500</output>

<result>500</result>