a: -146/43<0<1/89
b: 21/23<1<13/12
c: 3131/1313=31/13
e: 2019/2018=1+1/2018
2020/2019=1+1/2019
mà 1/2018>1/2019
nên 2019/2018>2020/2019
f: 2018/2019=1-1/2019
2019/2020=1-1/2020
mà -1/2019<-1/2020
nên 2018/2019<2019/2020
a) -146/43 < 0
0 < 1/89
Vậy -146/43 < 1/89
b) 21/23 < 1
1 < 13/12
Vậy 21/23 < 13/12
c) 3131/1313 = 31/13