A batch of books have been repaired, and 80 books have been repaired, which is 25% of the number of unrepaired books. How many books are there in total?
修补一批图书，已经修补了80本，是未修补本数的25%．这批图书一共多少本？
<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">80 / (1/4)</gadget>
<output>320</output>

<gadget id="calculator">320 + 80</gadget>
<output>400</output>

<result>400</result>