Lianhuashan Park has a square flower bed with a side length of 9 meters. The park staff intends to increase the side length of this square flower bed to 18 meters. How many square meters has the area of the flower bed increased in this way?
莲花山公园有一个边长是9米的正方形花坛，公园工作人员打算把这个正方形花坛的边长增加到18米．这样花坛的面积比原来增加了多少平方米？
<gadget id="calculator">18 * 18</gadget>
<output>324</output>

<gadget id="calculator">9 * 9</gadget>
<output>81</output>

<gadget id="calculator">324 - 81</gadget>
<output>243</output>

<result>243</result>