Bài 3 : Rút gọn các phân số sau: (15)/(25)=ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots (18)/(36)=ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots (16)/(200)=ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots ldots