The uphill speed of Xiao Gang is 5 kilometers per hour, and the downhill speed of returning to the original road is 10 kilometers. Find the average speed of Xiao Gang's uphill and downhill.
小刚骑车上坡速度是每小时5千米，原路返回下坡速度是10千米，求小刚上、下坡的平均速度．
<gadget id="calculator">10 + 10</gadget>
<output>20</output>

<gadget id="calculator">10 / 5</gadget>
<output>2</output>

<gadget id="calculator">10 / 10</gadget>
<output>1</output>

<gadget id="calculator">2 + 1</gadget>
<output>3</output>

<gadget id="calculator">20 / 3</gadget>
<output>20/3 = around 6.666667</output>

<result>20/3 = around 6.666667</result>