A farm tool factory produces a batch of farm tools, which was originally planned to be completed in 15 days. The actual production is 300 pieces per day, so not only the task is completed in 10 days, but also 450 pieces are over-produced. How many farm implements were originally planned to be produced per day?
某农具厂生产一批农具，原计划15天完成．实际每天生产300件，这样不仅10天完成了任务，还超额生产了450件．原计划每天生产多少件农具？
<gadget id="calculator">300 * 10</gadget>
<output>3_000</output>

<gadget id="calculator">3_000 - 450</gadget>
<output>2_550</output>

<gadget id="calculator">2_550 / 15</gadget>
<output>170</output>

<result>170</result>