Uncle Li donated some exercise books to 23 classes of Hope Primary School. After the school distributed 168 books to each class, there were still 80 books left. How many exercise books did Uncle Li donate to Hope Primary School?
李叔叔给希望小学23个班捐了一些练习本，学校给每班发168本后，还剩下80本，李叔叔给希望小学捐了多少本练习本？
<gadget id="calculator">168 * 23</gadget>
<output>3_864</output>

<gadget id="calculator">3_864 + 80</gadget>
<output>3_944</output>

<result>3_944</result>