classroom is 9 meters long, 5 meters wide, and 3 meters high. It is necessary to paint the walls and roof of the classroom (25.2 square meters after deducting doors, windows and blackboards). If 0.8 kilograms of paint is needed per square meter, how many kilograms of paint are needed to paint this classroom?
一间教室长9米，宽5米，高3米．要粉刷教室的四壁及屋顶(扣除门窗和黑板的面积25.2平方米)．如果每平方米需要涂料0.8千克，粉刷这间教室共需涂料多少千克？
<gadget id="calculator">9 * 5</gadget>
<output>45</output>

<gadget id="calculator">9 + 5</gadget>
<output>14</output>

<gadget id="calculator">14 * 3 * 2</gadget>
<output>84</output>

<gadget id="calculator">84 - 25.2</gadget>
<output>58.8</output>

<gadget id="calculator">45 + 58.8</gadget>
<output>103.8</output>

<gadget id="calculator">0.8 * 103.8</gadget>
<output>83.04</output>

<result>83.04</result>