The school has to paint the walls and ceiling of a classroom. It is known that the length of the classroom is 9 meters, the width is 7 meters, and the height is 3 meters. The area after deducting the doors and windows is 12.5 square meters. How many square meters is the area to be painted?
学校要粉刷一间教室的四壁和天花．已知教室的长是9米，宽7米，高是3米，扣除门窗的面积12.5平方米，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 - 12.5</gadget>
<output>29.5</output>

<gadget id="calculator">63 + 54 + 29.5</gadget>
<output>146.5</output>

<result>146.5</result>