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 the walls and ceiling of this room are to be painted with cement. How many square meters is the area to be painted with cement?
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，粉刷水泥的面积是多少平方米？
<gadget id="calculator">6 * 3.5</gadget>
<output>21</output>

<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<gadget id="calculator">3 * 3.5</gadget>
<output>10.5</output>

<gadget id="calculator">18 + 10.5</gadget>
<output>28.5</output>

<gadget id="calculator">28.5 * 2</gadget>
<output>57</output>

<gadget id="calculator">57 - 8</gadget>
<output>49</output>

<gadget id="calculator">21 + 49</gadget>
<output>70</output>

<result>70</result>