There is a grassland with a length of 25m and a width of 16m in the park. Now reduce the length and width of the grassland by 1m for road construction. How many square meters has the grass area been reduced from the original?
公园里有一块长为25m，宽16m的草地，现在把草地的长和宽各减少1m用来筑路．草地的面积比原来减少了多少平方米？
<gadget id="calculator">16 - 1</gadget>
<output>15</output>

<gadget id="calculator">25 + 15</gadget>
<output>40</output>

<gadget id="calculator">40 * 1</gadget>
<output>40</output>

<result>40</result>