2019 . 2021 - 2020. 2020
= 2019(2020+1) - 2020( 2019+1)
= 2019 .2020 + 1.2019 - 2020.2019 + 1.2020
= 2019 -2020
= -1
\(2019.2021-2020.2020\)
\(=2019\left(2020+1\right)-2020\left(2019+1\right)\)
\(=2019.2020+2019-2020.2019+2020\)
\(=2019-2020\)
\(=-1\)
2019 . 2021 - 2020 . 2020
= 2019 . ( 2020 + 1 ) - 2020 . ( 2019 + 1 )
= 2019 . 2020 + 2019 . 1 - 2020 . 2019 + 2020 .1
= (2019 . 2020 - 2020 . 2019 ) + ( 2019 . 1 - 2020 . 1 )
= 0 + ( -1 )
= -1
