A chemical fertilizer factory plans to produce 39 million tons of chemical fertilizers this year, and has already produced 18 million tons in the first half of the year. How many tons will be produced on average per month in the second half of the year to complete the production task for the whole year?
某化肥厂今年计划生产化肥3900万吨，上半年已经生产了1800万吨．下半年平均每月生产多少万吨，才能完成全年的生产任务？
<gadget id="calculator">3_900 - 1_800</gadget>
<output>2_100</output>

<gadget id="calculator">2_100 / 6</gadget>
<output>350</output>

<result>350</result>