Use exterior wall bricks with a length of 50 cm, a width of 20 cm, and a thickness of 0.4 cm to decorate two walls with a length of 12 meters and a height of 1 meter. How many bricks are needed.
用长50厘米，宽20厘米，厚度是0.4厘米的外墙砖装饰长12米高1米的两面墙．需要多少块这样的砖．
<gadget id="calculator">50 / 100</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">(1/2) * (1/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">2 / (1/10)</gadget>
<output>20</output>

<gadget id="calculator">12 * 1 * 20</gadget>
<output>240</output>

<result>240</result>