passenger car drives from place A to place B. It travels the whole distance (1/5) on the first day, and travels 450 kilometers on the second day. At this time, the remaining distance is just the whole distance (7/10). How many kilometers are there between A and B?
一辆客车从甲地开往乙地，第一天行了全程的(1/5)，第二天行了450千米，这时剩下的路程正好是全程的(7/10)．甲、乙两地相距多少千米？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">1 - (1/5) - (7/10)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">450 / (1/10)</gadget>
<output>4_500</output>

<result>4_500</result>