The school has 20 classrooms. Each classroom is 8 meters long, 6 meters wide and 4 meters high. The school needs to paint the ceiling and surrounding walls of the classroom. The area of doors and windows in each classroom is 22.4 meters**2. 200 grams of wall powder, how many kilograms of wall powder do I need to buy in total?
学校有20间教室，每间教室长8米，宽6米，高4米，学校要粉刷教室的顶棚和四周墙壁，每间教室的门窗面积是22.4米**2，平均每平方米用刷墙粉200克，一共需要买刷墙粉多少千克？
<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">48 + 32 + 24</gadget>
<output>104</output>

<gadget id="calculator">104 * 2</gadget>
<output>208</output>

<gadget id="calculator">208 - 48 - 22.4</gadget>
<output>137.6</output>

<gadget id="calculator">200 / 1_000</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">137.6 * 20 * (1/5)</gadget>
<output>550.4</output>

<result>550.4</result>