It took Xiao Ming 10 minutes to go uphill, and 8 minutes to return to the original place. The length of this road is 180 meters. Find out how many meters per minute is Xiaoming's average round-trip speed?
小明在走上坡路时用了10分钟，返回原地时用了8分钟，这条了长180米．求小明往返的平均速度是每分钟走多少米？
<gadget id="calculator">10 + 8</gadget>
<output>18</output>

<gadget id="calculator">2 / 18</gadget>
<output>1/9 = around 0.111111</output>

<gadget id="calculator">180 * (1/9)</gadget>
<output>20</output>

<result>20</result>