The two classes of the fourth grade donated love to the children in the disaster area. Each person donated an average of 13 books. There were 51 students in the first class and 49 students in the second class. How many books did the two classes donate in total?
四年级两个班为灾区小朋友献爱心，平均每人捐献了13本书，一班有51人，二班有49人，两个班一共捐献了多少本？
<gadget id="calculator">51 + 49</gadget>
<output>100</output>

<gadget id="calculator">100 * 13</gadget>
<output>1_300</output>

<result>1_300</result>