classroom is 8 meters long, 6 meters wide, and 4 meters high. The doors, windows and blackboards of the classroom are 42.5 square meters in total. The top surface and four walls of the classroom need to be painted. How many square meters is the painted area?
一间教室长8米，宽6米，高4米，教室门窗和黑板一共有42.5平方米，要粉刷教室的顶面和四面墙壁，粉刷的面积有多少平方米？
<gadget id="calculator">8 * 4</gadget>
<output>32</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">32 + 24</gadget>
<output>56</output>

<gadget id="calculator">2 * 56</gadget>
<output>112</output>

<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<gadget id="calculator">48 - 42.5</gadget>
<output>5.5</output>

<gadget id="calculator">112 + 5.5</gadget>
<output>117.5</output>

<result>117.5</result>