Xinfeng Agricultural Tools Factory plans to produce 400 pieces of agricultural tools per month. Due to the adoption of new equipment, the output in 10 months exceeds 5% of the annual planned output. How many pieces are actually produced per month on average?
新风农具厂计划每月生产400件农具，由于采用了新设备，10个月的产量就超过全年计划产量的5%，实际平均每月生多少件．
<gadget id="calculator">5 / 100</gadget>
<output>1/20 = around 0.05</output>

<gadget id="calculator">1 + (1/20)</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">(21/20) / 10</gadget>
<output>21/200 = around 0.105</output>

<gadget id="calculator">12 * 400 * (21/200)</gadget>
<output>504</output>

<result>504</result>