Paint a classroom with a length of 9 meters, a width of 5 meters, and a height of 3 meters. The area of doors, windows and blackboards in the classroom is 15 square meters. How many square meters is the painting area of this classroom?
粉刷一个长9米，宽5米，高3米的教室，教室门窗和黑板面积15平方米，这个教室的粉刷面积是多少平方米？
<gadget id="calculator">9 * 3</gadget>
<output>27</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">27 + 15</gadget>
<output>42</output>

<gadget id="calculator">42 * 2</gadget>
<output>84</output>

<gadget id="calculator">9 * 5</gadget>
<output>45</output>

<gadget id="calculator">45 - 15</gadget>
<output>30</output>

<gadget id="calculator">84 + 30</gadget>
<output>114</output>

<result>114</result>