Question

tính bằng cách thuận tiên nhất :

a, 2022 x 2022 - 2022 x 2021

b, 215 x8 -15 x 8

c, 98 x 101 -98

Answer 1

a: =2022(2022-2021)=2022

b: =8(215-15)=8x200=1600

c: =98x100=9800

Answer 2

`2022 xx 2022 - 2022 xx 2021`

`=2022xx(2022-2021)`

`=2022xx1`

`=2022`

____________________________

`215 xx8 -15 xx 8`

`=8 xx (215-15)`

`=8xx200`

`=1600`

___________________________

`98 xx 101 -98`

`=98 xx 101 -98xx1`

`=98xx(101-1)`

`=98xx100`

`=9800`