road repair team repairs a section of road (2/7) on the first day, and repairs the first day (1/2) on the second day. At this time, the road will be completed after repairing 1400 meters. How long is this road?
一个修路队第一天修一段路的(2/7)，第二天修第一天的(1/2)，这时再修1400米就休完全路，这路有多长？
<gadget id="calculator">2 / 7</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">(2/7) * (1/2)</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 - (2/7) - (1/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">1_400 / (4/7)</gadget>
<output>2_450</output>

<result>2_450</result>