The length of a room is 6 meters, the width is 3.5 meters, and the height is 3 meters. The area of doors and windows is 8 square meters. Now we need to paint the walls and roof of this room with cement. If 4 kilograms of cement is needed per square meter, how many kilograms of cement will be needed in total?
一个房间的长6米，宽3.5米，高3米，门窗面积是8平方米．现在要把这个房间的四壁和顶面粉刷水泥，如果每平方米需要水泥4千克，一共要水泥多少千克？
<gadget id="calculator">6 * 3 * 2</gadget>
<output>36</output>

<gadget id="calculator">3.5 * 3 * 2</gadget>
<output>21</output>

<gadget id="calculator">6 * 3.5</gadget>
<output>21</output>

<gadget id="calculator">21 - 8</gadget>
<output>13</output>

<gadget id="calculator">36 + 21 + 13</gadget>
<output>70</output>

<gadget id="calculator">4 * 70</gadget>
<output>280</output>

<result>280</result>