Xiao Li went up the mountain at an average speed of 2 kilometers per hour, and down the mountain along the original road at an average speed of 3 kilometers per hour. Ask him how many kilometers per hour he travels up and down the mountain on average.
小李上山的速度为平均每小时2千米，沿原路下山的速度为平均每小时3千米．求他上下山往返平均每小时行多少千米．
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">(1/2) + (1/3)</gadget>
<output>5/6 = around 0.833333</output>

<gadget id="calculator">2 / (5/6)</gadget>
<output>12/5 = around 2.4</output>

<result>12/5 = around 2.4</result>