The school bought a batch of books, including 270 science and technology books, 90 less story books than (2/5) of the total number of books in this batch, and technology books and story books accounted for (5/8) of the total number of books in this batch , How many books are there in total?
学校买进一批图书，其中科技书有270本，故事书比这批图书的总数的(2/5)少90本，科技书和故事书共占这批图书的总数的(5/8)，这批图书一共有多少本？
<gadget id="calculator">270 - 90</gadget>
<output>180</output>

<gadget id="calculator">5 / 8</gadget>
<output>5/8 = around 0.625</output>

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

<gadget id="calculator">(5/8) - (2/5)</gadget>
<output>9/40 = around 0.225</output>

<gadget id="calculator">180 / (9/40)</gadget>
<output>800</output>

<result>800</result>