A classroom is 10 meters long, 5.5 meters wide, and 4 meters high, with a door and window area of 18 square meters. To paint the walls and ceiling of the classroom, if an average of 250 grams of lime is used per square meter, how many kilograms of lime are needed in total?
一间教室长10米，宽5.5米，高4米，门窗面积18平方米．要粉刷教室四壁和天花板，如果平均每平方米用石灰250克，一共要石灰多少千克？
<gadget id="calculator">66 * 2</gadget>
<output>132</output>

<gadget id="calculator">132 - 18</gadget>
<output>114</output>

<gadget id="calculator">55 + 114</gadget>
<output>169</output>

<gadget id="calculator">250 / 1_000</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">169 * (1/4)</gadget>
<output>169/4 = around 42.25</output>

<result>169/4 = around 42.25</result>