Ta có: \(1978\times1979+21\times1980+1958\)

\(=1978\times\left(1978+1\right)+21\times\left(1978+2\right)+1958\)

\(=1978\times1978+1978+21\times1978+42+1958\)

=1978x1978+21x1978+1978+42+1958

=1978x(1978+21)+1978+2000

=1978x1999+3978

=(1979-1)x(1979+20)+3978

=1979x1979+19x1979-20+3978

=1979x1979+19x1979+3958

=1979x(1979+19+2)

=1979x2000

Ta có: 1980x1979-1978x1979

=1979x(1980-1978)=1979x2

Ta có: \(\frac{1978\times1979+21\times1980+1958}{1980\times1979-1978\times1979}\)

\(=\frac{1979\times2000}{1979\times2}=\frac{2000}{2}=1000\)

`2022+2022:1/3+2022+2022:1/5`

`=2022+2022xx3+2022+2022xx5`

`=2022xx(1+3+1+5)`

`=2022xx10=20220`

20220

=2022x100=202200

= 2022 x ( 57 + 42 + 1 )

= 2022 x 100

= 202200

\(2022\times57+2022\times42+2022=2022\times\left(57+42+1\right)=2022\times\left(57+43\right)=2022\times100=202200.\)

2022*63=127386

2022*36=72792

127386+72792=200178

2022x63+2022x36+2022=2022x(63+36+1)

                                        =2022x100

                                        =202200

Sửa đề: \(\frac{2022}{2}:\frac43:\frac{2022}{9}:\frac{18}{24}\)

\(=\frac{2022}{2}\times\frac34\times\frac{9}{2022}\times\frac{24}{18}\)

\(=\frac34\times\frac92\times\frac43=\frac92\)

bạn cho đầy đủ câu hỏi đi

\(\dfrac{2022\times2023-1}{2023\times2021+2022}\)

= \(\dfrac{\left(2021+1\right)\times2023-1}{2023\times2021+2022}\)

= \(\dfrac{2023\times2021+2023-1}{2023\times2021+2022}\)

= \(\dfrac{2023\times2021+2022}{2023\times2021+2022}\)

= 1

2023×2021+20222022×2023−1​

= (2021+1)×2023−12023×2021+20222023×2021+2022(2021+1)×2023−1​

= 2023×2021+2023−12023×2021+20222023×2021+20222023×2021+2023−1​

= 2023×2021+20222023×2021+20222023×2021+20222023×2021+2022​

= 1