For a batch of books, 180 copies are sold on the first day and 270 copies are sold on the second day. At this time, the number of books sold is (1/3) of the total number. How many books are there in total?
一批书，第一天卖出180本，第二天卖出270本，这时卖出的书是总数的(1/3)．这批书一共有多少本？
<gadget id="calculator">180 + 270</gadget>
<output>450</output>

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

<gadget id="calculator">450 / (1/3)</gadget>
<output>1_350</output>

<result>1_350</result>