Uncle Wang took (2/3)h to travel a section of 4km, how many kilometers does he travel per hour?
王叔叔行一段4km的路用了(2/3)h，他每小时行多少km．
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">4 / (2/3)</gadget>
<output>6</output>

<result>6</result>