There is an open space with a length of 20m and a width of 10m in front of the school. The largest pool is to be built in it, and the remaining open space is used for planting flowers. How many m**2 is the area for planting flowers?
学校门前有一块长20m、宽10m的空地，要在里面建一个最大的水池，剩下的空地种花，种花面积有多少m**2？
<gadget id="calculator">20 * 10</gadget>
<output>200</output>

<gadget id="calculator">10 * 10</gadget>
<output>100</output>

<gadget id="calculator">200 - 100</gadget>
<output>100</output>

<result>100</result>