Uncle Wang bought 12 sets of books at 29 yuan each. He paid the salesperson 400 yuan, how much should he get back?
王叔叔买了12套书，每套书29元．他付给营业员400元，应找回多少钱？
<gadget id="calculator">12 * 29</gadget>
<output>348</output>

<gadget id="calculator">400 - 348</gadget>
<output>52</output>

<result>52</result>