Xinhua Bookstore shipped in a batch of books, sold 32% of the books on the first day, and sold 48% of the books on the second day. It is known that 640 books were sold in these two days. How many books are there in this batch? ?
新华书店运进一批图书，第一天卖出这批图书的32%，第二天卖出这批图书的48%，已知这两天共卖出640本，这批图书一共有多少本？
<gadget id="calculator">32 / 100</gadget>
<output>8/25 = around 0.32</output>

<gadget id="calculator">48 / 100</gadget>
<output>12/25 = around 0.48</output>

<gadget id="calculator">(8/25) + (12/25)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">640 / (4/5)</gadget>
<output>800</output>

<result>800</result>