From home to school, Xiao Ming walks 60 meters per minute to school and 90 meters per minute to school. So how many meters per minute does Xiao Ming walk on average for a round trip?
小明从家到学校，上学每分钟走60米，放学每分钟走90米．那么小明往返一趟平均每分钟走多少米？
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 60</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">1 / 90</gadget>
<output>1/90 = around 0.011111</output>

<gadget id="calculator">(1/60) + (1/90)</gadget>
<output>1/36 = around 0.027778</output>

<gadget id="calculator">2 / (1/36)</gadget>
<output>72</output>

<result>72</result>