The fertilizer factory plans to produce 7,200 tons of fertilizer. It has been in production for 4 months, and the average monthly production of fertilizer is 1,200 tons. The remaining monthly production is 800 tons. How many months will it take to complete the production?
化肥厂计划生产7200吨化肥，已经生产了4个月，平均每月生产化肥1200吨，余下的每月生产800吨，还要生产多少个月才能完成？
<gadget id="calculator">1_200 * 4</gadget>
<output>4_800</output>

<gadget id="calculator">7_200 - 4_800</gadget>
<output>2_400</output>

<gadget id="calculator">2_400 / 800</gadget>
<output>3</output>

<result>3</result>