a) Ta có:
1996/1995 = 1 + 1/1995
1995/1994 = 1 + 1/1994
1994/1993 = 1 + 1/1993
1993/1992 = 1 + 1/1992
1992/1991 = 1 + 1/1991
Vì 1/1995 < 1/1994 < 1/1993 < 1/1992 < 1/1991
=> 1+1/1995 < 1+1/1994 < 1+1/1993 < 1+1/1992 < 1+1/1991
=>1996/1995<1995/1994<1994/1993<1993/1992<1992/1991
=> Sắp xếp tăng dần:
1996/1995; 1995/1994; 1994/1993; 1993/1992; 1992/1991
 

Làm tương tự ý a
b.1/3 < 3/5 < 5/7 < 7/9 < 9/11
c. 97/98 > 57/58 > 17/18 > 7/8