A piece of rectangular glass is 3.1 meters long and 2 meters wide. If the price per square meter of glass is 3 yuan, how much does it cost to buy this piece of glass?
一块长方形玻璃长3.1米，宽2米，如果每平方米玻璃的价格是3元，买这块玻璃需要多少钱？
<gadget id="calculator">3.1 * 2</gadget>
<output>6.2</output>

<gadget id="calculator">6.2 * 3</gadget>
<output>18.6</output>

<result>18.6</result>