The classroom of class 21 is on the second floor (four floors in total). The classroom is 10 meters long, 6 meters wide, and 4 meters high. The door and window area is 19.6 square meters. If 0.25 kilograms of paint is used per square meter to paint the inner walls, how many kilograms of paint are needed in total? ?
二1班教室在二楼(共四层)，教室长10米，宽6米，高4米，门窗面积19.6平方米，如果每平方米用涂料0.25千克来粉刷内墙壁，共需要涂料多少千克？
<gadget id="calculator">10 * 6</gadget>
<output>60</output>

<gadget id="calculator">10 * 4</gadget>
<output>40</output>

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

<gadget id="calculator">60 + 40 + 24</gadget>
<output>124</output>

<gadget id="calculator">124 * 2</gadget>
<output>248</output>

<gadget id="calculator">248 - 60 - 19.6</gadget>
<output>168.4</output>

<gadget id="calculator">168.4 * 0.25</gadget>
<output>42.1</output>

<result>42.1</result>