A threshing floor is 65 meters long and 50 meters wide. After expansion, the length increases by 15 meters and the width increases by 10 meters. What is the area of the threshing floor after expansion?
一个打谷场长65米，宽50米，扩建后长增加15米，宽增加10米，扩建后的打谷场面积是多少平方米？
<gadget id="calculator">65 + 15</gadget>
<output>80</output>

<gadget id="calculator">50 + 10</gadget>
<output>60</output>

<gadget id="calculator">80 * 60</gadget>
<output>4_800</output>

<result>4_800</result>