Ta có : $A$ = $\frac{2018.2019+1}{2018.2019}$ $= 1 +$ $\frac{1}{2018.2019}$
Ta lại có : $B =$ $\frac{2019.2020+1}{2019.2020}$ $= 1 +$ $\frac{1}{2019.2020}$
Vì $\frac{1}{2018.2019}$ $>$ $\frac{1}{2019.2020}$ nên $1 +$ $\frac{1}{2018.2019}$ $> 1 +$ $\frac{1}{2019.2020}$
$⇒ A > B$
Vậy $A > B$
HỌC TỐT!