A classroom is 8 meters long, 7 meters wide, and 3 meters high. The walls and ceiling need to be painted, and the doors, windows and blackboards occupy 8 square meters. If 150 grams of lime is used per square meter, how many kilograms of lime will be needed?
一个教室长8米，宽7米，高3米，要粉刷四壁和天花，其中门窗和黑板的面积占了8平方米，如果每平方米要用石灰150克共要石灰多少千克？
<gadget id="calculator">8 * 7</gadget>
<output>56</output>

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

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<gadget id="calculator">56 + 24 + 21</gadget>
<output>101</output>

<gadget id="calculator">101 * 2</gadget>
<output>202</output>

<gadget id="calculator">202 - 56 - 8</gadget>
<output>138</output>

<gadget id="calculator">150 / 1_000</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">138 * (3/20)</gadget>
<output>207/10 = around 20.7</output>

<result>207/10 = around 20.7</result>