The TV factory completed the plan for the month (3/5) in the first half of the month, and completed the plan for the month (4/7) in the second half of the month. As a result, the production exceeded 600 sets in the whole month. How many TV sets were originally planned to be produced in this month?
电视机厂上半月完成当月计划的(3/5)，下半月完成当月计划的(4/7)，结果全月超产600台，该月原计划生产电视机多少台？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">4 / 7</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">(4/7) - 1</gadget>
<output>-3/7 = around -0.428571</output>

<gadget id="calculator">(3/5) + (-3/7)</gadget>
<output>6/35 = around 0.171429</output>

<gadget id="calculator">600 / (6/35)</gadget>
<output>3_500</output>

<result>3_500</result>