There are a batch of machine parts, and it takes 8 (1/2) days to make A alone, which is (1/2) more days than B alone. After 4 days of cooperation between the two, the remaining 210 parts are made by A alone. How many parts were made.
有批机器零件，甲单独制作需要8(1/2)天，比乙单独制作多用了(1/2)天，两人合作4天后，剩下210个零件由甲单独去做，自始至终甲共制作了多少零件．
<result>3_750</result>