The freighter Changjiang sailed from port A to port B, and has traveled 180 kilometers, just sailing (3/5) of the waterway between port A and port B. How many kilometers will it take to reach the destination?
长江号货轮从甲港开往乙港，已经行了180千米，正好航行了甲、乙两港航道的(3/5)，还要行多少千米才能到达目的地？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">180 / (3/5)</gadget>
<output>300</output>

<gadget id="calculator">300 - 180</gadget>
<output>120</output>

<result>120</result>