a) 17/20 = 323/380
18/19 = 360/380
Do 323 < 360 nên 323/380 < 360/380
Vậy 17/20 < 18/19
b) 19/18 = 1 + 1/18
2023/2022 = 1 + 1/2022
Do 18 < 2022 nên 1/18 > 1/2022
1 + 1/18 > 1 + 1/2022
Vậy 19/18 > 2023/2022
c) 13/17 = 455/595
135/175 = 27/35 = 459/595
Do 455 < 459 nên 455/595 < 459/595
Vậy 13/17 < 135/175
d) 53/63 = 11236/13356
535/636 = 11235/13356
Do 11236 > 11235 nên 11236/13356 > 11235/13356
Vậy 53/63 > 535/636
e) 13/15 = 65/75
22/25 = 66/75
Do 65 < 66 nên 65/75 < 66/75
Vậy 13/15 < 22/25