Xiaojun’s new house is being renovated. The length of Xiaojun’s bedroom is 4 meters, the width is 2.5 meters, and the height is 2.8 meters. Wall coverings must be pasted on the four walls of the room. The area of doors and windows is 8 square meters, and at least wall coverings must be used. How many square meters?
小军家的新房正在装修，小军卧室的长是4米，宽是2.5米，高是2.8米，要在房间的四壁贴上墙布，扣除门窗面积8平方米，至少要用墙布多少平方米？
<gadget id="calculator">4 * 2.8</gadget>
<output>11.2</output>

<gadget id="calculator">2.5 * 2.8</gadget>
<output>7</output>

<gadget id="calculator">11.2 + 7</gadget>
<output>18.2</output>

<gadget id="calculator">18.2 * 2</gadget>
<output>36.4</output>

<gadget id="calculator">36.4 - 8</gadget>
<output>28.4</output>

<result>28.4</result>