Nangang Forest Farm has planted 6,400 trees this year, which is 1/7 more than the original plan. How many trees were planted in the original plan?
南港林场今年植树6400棵，比原计划多植了(1/7)，原计划植树多少棵？
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">1 + (1/7)</gadget>
<output>8/7 = around 1.142857</output>

<gadget id="calculator">6_400 / (8/7)</gadget>
<output>5_600</output>

<result>5_600</result>