The fertilizer plant completed the plan (3/5) in the first half of the year, and (4/7) the plan in the second half of the year. This not only completed the planned task, but also overproduced 120,000 tons of fertilizer. How many tons of fertilizer does this fertilizer plant plan to produce annually?
化肥厂上半年完成计划的(3/5)，下半年完成计划的(4/7)，这样不但完成了计划任务，还超额生产化肥12万吨，这个化肥厂年计划生产化肥多少万吨？
<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">12 / (6/35)</gadget>
<output>70</output>

<result>70</result>