Master Li plans to process 2,620 parts. He has already processed 5 days, 260 parts per day, and the rest will take 4 days to complete. How many parts are processed per day on average? (Solve by two methods of arithmetic and equation)
李师傅计划加工2620个零件，已经加工了5天，每天加工260个，剩下的要4天完成，平均每天加工多少个零件？(用算术、方程两种方法解答)
<gadget id="calculator">260 * 5</gadget>
<output>1_300</output>

<gadget id="calculator">2_620 - 1_300</gadget>
<output>1_320</output>

<gadget id="calculator">1_320 / 4</gadget>
<output>330</output>

<result>330</result>