Zhenhai Yale organizes teachers to carry out outward bound training, walk along the road from A to B, and then immediately return to A by the same route. If the employee travels 1 km more than the previous day, it takes 4 days to complete the journey and 3 days to return. Ask how far and how many kilometers is the total distance from A to B
镇海雅乐组织教师进行拓展训练，沿公路从甲地步行至乙地，再由乙地立即原路返回甲地．如果员工每天行进的路程比前一天增加1千米，则去时用4天走完的路程，返回时用了3天，问甲地到乙地总共多远多少千米
<gadget id="calculator">6 - 1 - 2 - 3</gadget>
<output>0</output>

<gadget id="calculator">4 + 5 + 0</gadget>
<output>9</output>

<gadget id="calculator">1 - 1 - 1 - 1</gadget>
<output>-2</output>

<gadget id="calculator">1 + 1 + 1 + (-2)</gadget>
<output>1</output>

<gadget id="calculator">9 / 1</gadget>
<output>9</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<gadget id="calculator">9 + 2</gadget>
<output>11</output>

<gadget id="calculator">9 + 3</gadget>
<output>12</output>

<gadget id="calculator">9 + 10 + 11 + 12</gadget>
<output>42</output>

<result>42</result>