A classroom is 8 meters long, 6 meters wide, and 4 meters high. It is necessary to paint the walls and ceiling of the classroom. After deducting the area of 22 square meters of doors, windows and blackboards, an average of 0.3 kilograms of lime is used per square meter. How many kilograms of lime are needed in total?
一间教室长8米，宽6米，高4米，要粉刷教室四壁和顶棚，扣除门窗和黑板面积22平方米，平均每平方米用石灰0.3千克，一共需要石灰多少千克？
<gadget id="calculator">8 * 6</gadget>
<output>48</output>

<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">56 * 2</gadget>
<output>112</output>

<gadget id="calculator">112 - 22</gadget>
<output>90</output>

<gadget id="calculator">48 + 90</gadget>
<output>138</output>

<gadget id="calculator">138 * 0.3</gadget>
<output>41.4</output>

<result>41.4</result>