Mr. Li spent 23.28 yuan on mathematics reference books, which was 0.72 yuan more than the language reference books. He paid the salesperson 50 yuan. How much should he get back for two books?
李老师买数学参考书用了23.28元，比语文参考书多用了0.72元，他付给售货员50元，买两本书应找回多少钱？
<gadget id="calculator">23.28 - 0.72</gadget>
<output>22.56</output>

<gadget id="calculator">22.56 + 23.28</gadget>
<output>45.84</output>

<gadget id="calculator">50 - 45.84</gadget>
<output>4.16</output>

<result>4.16</result>