The distance between A and B is 420 kilometers. A car has traveled the whole distance (5/7). How many kilometers are left?
甲乙两地相距420千米，一辆汽车行驶了全程的(5/7)，还剩了多少千米没走？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">1 - (5/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">420 * (2/7)</gadget>
<output>120</output>

<result>120</result>