(Mistake-prone question) A billboard is a trapezoid, the upper base is 4m, the lower base is 6m, and the height is 2.5m. Now it is necessary to paint the front and back of it, how big is the area to be painted?
(易错题)一块广告牌是一个梯形，上底是4m，下底是6m，高2.5m．现在要在它的正反面刷油漆，刷油漆的面积有多大？
<gadget id="calculator">4 + 6</gadget>
<output>10</output>

<gadget id="calculator">2.5 / 2</gadget>
<output>1.25</output>

<gadget id="calculator">10 * 1.25 * 2</gadget>
<output>25</output>

<result>25</result>