In front of No. 3 Building of Huacheng Community, there is a rectangular open space with a length of 30 meters and a width of 20 meters. Residents plan to build a gravel road with a width of 2 meters in the middle of the open space.
花城小区3号楼前有一块长30米、宽20米的长方形空地，居民们准备在空地中间纵横各造一条宽2米的石子路，其余的空地建成草坪，草坪的面积是多少米？
<gadget id="calculator">30 * 20</gadget>
<output>600</output>

<gadget id="calculator">30 * 2</gadget>
<output>60</output>

<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<gadget id="calculator">2 * 2</gadget>
<output>4</output>

<gadget id="calculator">40 - 4</gadget>
<output>36</output>

<gadget id="calculator">60 + 36</gadget>
<output>96</output>

<gadget id="calculator">600 - 96</gadget>
<output>504</output>

<result>504</result>