An auditorium is 20 meters long, 15 meters wide, and 8 meters high. It is necessary to paint the ceiling and surrounding walls of the auditorium. Excluding the door and window area of 120 square meters, an average of 0.5 kilograms of paint is used per square meter. How many kilograms of paint are needed in total?
一个礼堂长20米，宽15米，高8米，要粉刷礼堂的顶棚和四周墙壁，除去门窗面积120平方米，平均每平方米用涂料0.5千克，一共需涂料多少千克？
<gadget id="calculator">20 * 15</gadget>
<output>300</output>

<gadget id="calculator">20 * 8 * 2</gadget>
<output>320</output>

<gadget id="calculator">15 * 8 * 2</gadget>
<output>240</output>

<gadget id="calculator">240 - 120</gadget>
<output>120</output>

<gadget id="calculator">300 + 320 + 120</gadget>
<output>740</output>

<gadget id="calculator">0.5 * 740</gadget>
<output>370</output>

<result>370</result>