garden community has a rectangular green square with a length of 10 meters and a width of 9 meters. There is a square fountain with a side length of 3 meters in the center of the square. If the square (except the fountain) is paved with 9 square decimeters of floor tiles, How many tiles do you need?
某园林小区有一个长10米，宽9米的长方形绿化广场，该广场的中央有一个边长为3米的正方形喷水池，如果这个广场(除喷水池外)用9平方分米的地砖铺地，需要这种地砖多少块？
<gadget id="calculator">10 * 9</gadget>
<output>90</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">90 - 9</gadget>
<output>81</output>

<gadget id="calculator">100 / 9</gadget>
<output>100/9 = around 11.111111</output>

<gadget id="calculator">81 * (100/9)</gadget>
<output>900</output>

<result>900</result>