A conference room is 9 meters long, 6 meters wide, and 4 meters high. The total area of doors and windows is 20 square meters. A total of 3,080 yuan was spent on pasting wallpaper on the walls and ceiling of the meeting room. How much does wallpaper cost per square meter?
一间会议室长9米，宽6米，高4米，门窗面积一共是20平方米．在会议室的四壁和顶棚贴上壁纸，一共花了3080元．每平方米壁纸花多少元？
<gadget id="calculator">9 * 6</gadget>
<output>54</output>

<gadget id="calculator">9 * 4 * 2</gadget>
<output>72</output>

<gadget id="calculator">6 * 4 * 2</gadget>
<output>48</output>

<gadget id="calculator">48 - 20</gadget>
<output>28</output>

<gadget id="calculator">54 + 72 + 28</gadget>
<output>154</output>

<gadget id="calculator">3_080 / 154</gadget>
<output>20</output>

<result>20</result>