A sidewalk with a width of 6 meters covers an area of 840 square meters. For the convenience of pedestrians, the width of the road should be increased by 10 meters, and the length should remain unchanged. After widening, what is the area of this sidewalk?
一条宽6米的人行道，占地面积是840平方米．为了行人方便，路宽要增加10米，长不变．扩宽以后，这条人行道的面积是多少？
<gadget id="calculator">840 / 6</gadget>
<output>140</output>

<gadget id="calculator">6 + 10</gadget>
<output>16</output>

<gadget id="calculator">140 * 16</gadget>
<output>2_240</output>

<result>2_240</result>