There is a square lawn with a side length of 40 meters in the central square of a certain county. If 1 square meter of lawn can release 25 grams of oxygen per day, how many kilograms of oxygen can be released by this lawn per day?
某县城中心广场有一块边长40米的正方形草坪．如果1平方米草坪每天能释放氧气25克，那么这块草坪一天约释放氧气多少千克？
<gadget id="calculator">25 / 1_000</gadget>
<output>1/40 = around 0.025</output>

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

<result>40</result>