The distance between A and B is 680 kilometers. A train travels from A to B. It travels the whole distance (3/4) on the first day, and travels the whole distance (1/5) on the second day. How many kilometers are left? Not far away?
甲乙两地相距680千米，一列火车从甲地开往乙地，第一天行了全程的(3/4)，第二天行了全程的(1/5)，还剩下多少千米距离未走？
<gadget id="calculator">3 / 4</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (3/4) - (1/5)</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">680 * (1/20)</gadget>
<output>34</output>

<result>34</result>