Xiao Ming's family uses 20 cubic meters of natural gas in a week, so how many cubic meters of natural gas will be used in a month (based on 30 days).
小明家一星期用了20立方米的天然气，那么一个月(按30天计算)要用天然气多少立方米．
<gadget id="calculator">20 / 7</gadget>
<output>20/7 = around 2.857143</output>

<gadget id="calculator">(20/7) * 30</gadget>
<output>600/7 = around 85.714286</output>

<result>600/7 = around 85.714286</result>