Yuqiang Primary School has 20 classes with an average of 40 students in each class. They donated a total of 3,200 books to primary schools in poor areas. How many books do each person donate on average?
育强小学有20个班，平均每班40人，他们共向穷困地区小学捐献图书3200本，平均每人捐图书多少本？
<gadget id="calculator">40 * 20</gadget>
<output>800</output>

<gadget id="calculator">3_200 / 800</gadget>
<output>4</output>

<result>4</result>