B=1.2.3...2023-1.2.3...2022-1.2.3...2021. $2022^{2}$

$\textit{đáp án+ bước giải}

B=1.2.3....2023-1.2.3....2022-1.2.3...2021.$2022^2$

B=1.2.3...2022.(2023-1-2022)

B=1.2.3...2022.0

B=0