A rectangular cultural square is 300 meters long and 200 meters wide. The largest square square should be reserved in the square, and the rest of the square should be greened. How many hectares is the greened area?
一个长方形文化广场长300米，宽200米，要在广场预留一块最大的正方形广场，其余的绿化，绿化的面积是多少公顷？
<gadget id="calculator">300 * 200</gadget>
<output>60_000</output>

<gadget id="calculator">200 * 200</gadget>
<output>40_000</output>

<gadget id="calculator">60_000 - 40_000</gadget>
<output>20_000</output>

<gadget id="calculator">20_000 / 10_000</gadget>
<output>2</output>

<result>2</result>