There are 7,000 books in the school library, of which science and technology books account for 20%, and literature and art books account for (2/7). How many books are there in total?
学校图书馆共有图书7000册，其中科技书占20%，文艺书占(2/7)，这两种书共有多少册？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(1/5) + (2/7)</gadget>
<output>17/35 = around 0.485714</output>

<gadget id="calculator">7_000 * (17/35)</gadget>
<output>3_400</output>

<result>3_400</result>