To paint a classroom, the classroom is 9 meters long, 5 meters wide, and 3 meters high. The area excluding doors, windows and blackboards is 22.5 square meters without painting. If it is calculated at 8 yuan per square meter, how much does it cost to paint this classroom? ?
要粉刷一间教室，教室长9米，宽5米，高3米，除去门、窗和黑板的面积是22.5平方米不粉刷，如果按每平方米8元计算，粉刷这间教室需要多少钱？
<gadget id="calculator">9 * 5</gadget>
<output>45</output>

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

<gadget id="calculator">5 * 3 * 2</gadget>
<output>30</output>

<gadget id="calculator">30 - 22.5</gadget>
<output>7.5</output>

<gadget id="calculator">45 + 54 + 7.5</gadget>
<output>106.5</output>

<gadget id="calculator">106.5 * 8</gadget>
<output>852</output>

<result>852</result>