trapezoidal decorative board, the upper base is 80 cm, the lower base is 100 cm, and the height is 1 m. Both sides should be painted with paint, how many square decimeters is the painted area?
一个梯形装饰板，上底是80厘米，下底是100厘米，高是1米．两面都要涂上油漆，涂油漆的面积是多少平方分米．
<gadget id="calculator">1 * 10</gadget>
<output>10</output>

<gadget id="calculator">80 / 10</gadget>
<output>8</output>

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

<gadget id="calculator">8 + 10</gadget>
<output>18</output>

<gadget id="calculator">100 / 10 / 2</gadget>
<output>5</output>

<gadget id="calculator">18 * 5 * 2</gadget>
<output>180</output>

<result>180</result>