Question

Tính nhanh: 

-2021 . 20222022 + 2022 . 20212021

Answer 1

-2021 . 20222022 + 2022 .20212021

= -2021 . 2022. 10001 + 2022.2021. 10001

= 0

Answer 2

-2021 . 20222022 + 2022 . 20212021

= (-2021) . (20222022 - 2022 . 10001)

= (-2021) . (20222022 - 20222022)

= (-2021) . 0

= 0