A conference room is 20 meters long, 8 meters wide, and 4 meters high. The surrounding walls and ceiling need to be painted, and the area of doors and windows is 40 square meters. How many square meters is the painted area?
一间会议室长20米，宽8米，高4米，要粉刷四周墙壁和天花板，除去门窗面积40平方米，粉刷的面积是多少平方米？
<gadget id="calculator">20 * 8</gadget>
<output>160</output>

<gadget id="calculator">20 * 4 * 2</gadget>
<output>160</output>

<gadget id="calculator">8 * 4 * 2</gadget>
<output>64</output>

<gadget id="calculator">64 - 40</gadget>
<output>24</output>

<gadget id="calculator">160 + 160 + 24</gadget>
<output>344</output>

<result>344</result>