A commodity is priced at a 30% increase from the cost price, and then sold at a 20% discount due to seasonal reasons. After the price reduction, each commodity sells for 312 yuan. How much is the cost of this item?
一件商品，按成本价提高30%定价，后因季节原因，打八折出售，降价后每件商品卖312元．这件商品成本价是多少元？
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">312 / (4/5)</gadget>
<output>390</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">390 / (13/10)</gadget>
<output>300</output>

<result>300</result>