Ta có:
A = 199.201
A = 199.(200+1)
A = 199.200+199
B = 200.200
B = (199+1).200
B = 199.200+200
Vì 199 < 200 => 199.200+199 < 199.200+200
=> A < B
Ủng hộ mk nha ^_-
A=199.201=199.(200+1)=199.200+199
B=200.200=200(199+1)=199.200+200
Vì 199<200 nên 199.200+199<199.200+200 hay A<B