There are about 300 to 400 books in a batch, and they are packed into 12 books per pack, leaving 11 books; 18 books per pack, 7 books are missing; 15 books per pack, 4 books are missing, how many books are there in this batch?
一批书大约有300到400本，包装成每包12本，剩下11本；每包18本，缺7本；每包15本，缺4本，这批书有多少本？
<gadget id="calculator">2 * 2 * 3 * 3 * 5</gadget>
<output>180</output>

<gadget id="calculator">180 * 2</gadget>
<output>360</output>

<gadget id="calculator">360 + 11</gadget>
<output>371</output>

<result>371</result>