Ta có: 262 - 242 = (26 - 24)(26 + 24) = 2 . 50
272 - 252 = (27 - 25)(27 + 25) = 2 . 52
Vì 50 < 52 nên 262 - 242 < 272 - 252
Ta có:
\(A=26^2-24^2=\left(26-24\right)\left(26+24\right)=2.50=100^{\left(1\right)}\)
\(B=27^2-25^2=\left(27-25\right)\left(27+25\right)=2.52=104^{\left(2\right)}\)
Từ (1),(2)\(\Rightarrow A< B\)