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, and the task is completed in 12 days. How many pieces are produced less than the original plan 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，12天就完成了任务，原计划每天比实际每天少生产多少件？
<gadget id="calculator">12 / 15</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">300 * (4/5)</gadget>
<output>240</output>

<gadget id="calculator">300 - 240</gadget>
<output>60</output>

<result>60</result>