There is a trapezoidal open space, the upper base is 6m, the lower base is 10m, and the height is 5m. The largest rectangular concrete floor is laid on this land, and the rest is planted with lawn. What is the area of the lawn?
有一块梯形的空地，上底是6m，下底是10m，高是5m，在这块地上铺一个最大的长方形水泥地，剩下的种植草坪，草坪的面积是多少？
<gadget id="calculator">6 + 10</gadget>
<output>16</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">16 * (5/2)</gadget>
<output>40</output>

<gadget id="calculator">6 * 5</gadget>
<output>30</output>

<gadget id="calculator">40 - 30</gadget>
<output>10</output>

<result>10</result>