How many square meters of iron sheets are needed to make 100 rainwater pipes with a length of 2 meters, a width of 20 cm, and a height of 10 cm for a new building?
为一座新楼做100节长2米、宽20厘米、高10厘米的雨水管道，需要铁皮多少平方米？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">10 / 100</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">(1/5) + (1/10)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(3/10) * 2 * 2 * 100</gadget>
<output>120</output>

<result>120</result>