Xiaohua reads a story book, reads 25% of the whole book on the first day, and reads 1/3 of the whole book on the second day, and there are 350 pages left. How many pages are there in this book?
小华看一本故事书，第一天看全书的25%，第二天看全书的(1/3)，还剩350页，这本书一共多少页？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/4) - (1/3)</gadget>
<output>5/12 = around 0.416667</output>

<gadget id="calculator">350 / (5/12)</gadget>
<output>840</output>

<result>840</result>