The area of a rectangular lawn is 40 square meters. Now it is necessary to increase its length from the original 5 meters to 10 meters and keep the width unchanged. What is the area of the enlarged lawn in square meters?
一块长方形草地的面积是40平方米，现在要将它的长从原来的5米增加到10米，宽不变，扩大后的草地面积是多少平方米？
<gadget id="calculator">10 / 5</gadget>
<output>2</output>

<gadget id="calculator">40 * 2</gadget>
<output>80</output>

<result>80</result>