Thực hiện phép tính
  1+3+5+…+2019−2−4−6−…−2018.

One crate has oranges. Someone takes out half of all the
oranges plus one half of one orange. Later on, another person
takes out half of the remaining amount and one half of one
orange. Finally, someone takes half of the new remaining
amount and one half of one orange. After all this, 3 oranges
are left in the crate. How many oranges were in the crate at
the beginning?
 

12. Fans think that Jack is the best member of the team.

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1. Everyone told us that you were the winner of the City Olympic Prize in the competition last year.

hiện nay tuổi bố gấp 5 lần tuổi con.10 năm nữa tuổi bố gấp 5/2 tuổi con. Tính tuổi con hiện nay.