Xinhua Bookstore shipped a batch of children's books, sold 1,800 copies on the first day, and sold (8/9) of the first day's books on the second day, and sold out the rest (2/7) on the third day. How many books are there in total?
新华书店运来一批儿童读物，第一天卖出1800本，第二天卖出的本数是第一天的(8/9)，余下总数的(2/7)第三天全部卖完，这批书一共有多少本．
<gadget id="calculator">8 / 9</gadget>
<output>8/9 = around 0.888889</output>

<gadget id="calculator">1_800 * (8/9)</gadget>
<output>1_600</output>

<gadget id="calculator">1_600 + 1_800</gadget>
<output>3_400</output>

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

<gadget id="calculator">1 - (2/7)</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">3_400 / (5/7)</gadget>
<output>4_760</output>

<result>4_760</result>