The farm tool factory originally planned to produce 400 farm tools per month. After the technological innovation, the production volume in nine months exceeded the annual plan of 780. How many pieces are produced on average per month now?
农具厂原计划每月生产农具400件，技术革新后，9个月生产量就超过全年计划780件，现在平均每月生产多少件？
<gadget id="calculator">400 * 12</gadget>
<output>4_800</output>

<gadget id="calculator">4_800 + 780</gadget>
<output>5_580</output>

<gadget id="calculator">5_580 / 9</gadget>
<output>620</output>

<result>620</result>