The school has a large classroom with a length, width and height of 24 meters, 10 meters and 3 meters respectively. To paint the roof and surrounding walls of this classroom, it is known that the area occupied by the doors and windows is 120 square meters, and 1.4 kg of paint is required per square meter. How many kilograms of paint is the minimum required to paint this classroom?
学校有一间大教室，长、宽、高分别为24米、10米和3米．要给这间教室粉刷房顶和四周墙壁，已知门窗所占的面积是120平方米，每平方米需要涂料1.4千克．粉刷这间教室至少要用多少千克涂料？
<gadget id="calculator">24 * 10</gadget>
<output>240</output>

<gadget id="calculator">24 * 3</gadget>
<output>72</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">72 + 30</gadget>
<output>102</output>

<gadget id="calculator">102 * 2</gadget>
<output>204</output>

<gadget id="calculator">204 - 120</gadget>
<output>84</output>

<gadget id="calculator">240 + 84</gadget>
<output>324</output>

<gadget id="calculator">324 * 1.4</gadget>
<output>453.6</output>

<result>453.6</result>