room is 5 meters long, 3 meters wide, and 2.8 meters high. Now the walls and ceiling need to be painted, and the area of doors and windows is 4.5 square meters. What is the total area to be painted?
一个房间长5米，宽3米，高2.8米，现需油漆四壁和天花板，扣除门窗的面积4.5平方米，油漆的总面积是多少平方米．
<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">5 * 2.8 * 2</gadget>
<output>28</output>

<gadget id="calculator">3 * 2.8 * 2</gadget>
<output>16.8</output>

<gadget id="calculator">16.8 - 4.5</gadget>
<output>12.3</output>

<gadget id="calculator">15 + 28 + 12.3</gadget>
<output>55.3</output>

<result>55.3</result>