The school needs to paint the ceiling and walls of a classroom with a length of 10 meters, a width of 8 meters and a height of 3 meters, and the area of doors and windows is 18 square meters. If paint costs 5 yuan per square meter, how much will it cost to paint this classroom?
学校要粉刷一间长10米、宽8米、高3米的教室的天花顶和四壁，扣除门窗面积18平方米．如果每平方米需要涂料费5元，粉刷这个教室要花多少元？
<gadget id="calculator">10 * 8</gadget>
<output>80</output>

<gadget id="calculator">10 * 3</gadget>
<output>30</output>

<gadget id="calculator">8 * 3</gadget>
<output>24</output>

<gadget id="calculator">30 + 24</gadget>
<output>54</output>

<gadget id="calculator">54 * 2</gadget>
<output>108</output>

<gadget id="calculator">108 - 18</gadget>
<output>90</output>

<gadget id="calculator">80 + 90</gadget>
<output>170</output>

<gadget id="calculator">170 * 5</gadget>
<output>850</output>

<result>850</result>