The school needs to paint the multimedia classroom. The length of the multimedia classroom is 9 meters, the width is 7 meters, the height is 3 meters, and the area of doors and windows is 12.6 square meters. How many square meters do you need to paint?
学校要粉刷多媒体教室，经测量多媒体教室的长是9米，宽是7米，高是3米，门窗面积是12.6平方米．求需要粉刷的面积是多少平方米？
<gadget id="calculator">9 * 7</gadget>
<output>63</output>

<gadget id="calculator">9 * 3 * 2</gadget>
<output>54</output>

<gadget id="calculator">7 * 3 * 2</gadget>
<output>42</output>

<gadget id="calculator">42 - 12.6</gadget>
<output>29.4</output>

<gadget id="calculator">63 + 54 + 29.4</gadget>
<output>146.4</output>

<result>146.4</result>