Xiaoming travels from place A to place B at a speed of 5km/h, and Xiaohua travels from place B to place A at a speed of 4km/h. The two start at the same time and meet at a distance of 1 km from the midpoint of A and B. What is the distance in km between A and B?
小明以5km/h的速度从甲地到乙地，小华以4km/h的速度从乙地到甲地．两人同时出发，在离甲、乙两地中点1km处相遇．甲、乙两地间的路程是多少km．
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

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

<gadget id="calculator">(5/9) - (1/2)</gadget>
<output>1/18 = around 0.055556</output>

<gadget id="calculator">1 / (1/18)</gadget>
<output>18</output>

<result>18</result>