Đề thiếu rồi bạn

38 x 6 + 38 x 3 + 38 

= 38 x (6+3+1)

= 38 x 10

= 380

38 x 6 + 38 x 3 +38= 38 x 6 + 38 x 3 +38 x 1

= 38 x (3 + 6 + 1)

= 38 x 10

=380

38 x 6 + 38 x 3 + 38

=38 x 6 + 38 x 3 + 38 x 1

=38 x( 6 + 3 + 1)

=38 x 10

=380

a) \(19\times\left(52+38\right)-9\times\left(52+38\right)=\)

\(=\)     \(19\times90-9\times90\) 

\(=90\times\left(19-9\right)\) 

\(=90\times10\) 

\(=900\) 

b) \(\dfrac{2}{5}\div\dfrac{3}{7}\times\dfrac{3}{7}\div\dfrac{2}{5}+2019=\)

\(=\left(\dfrac{2}{5}\div\dfrac{2}{5}\right)\times\left(\dfrac{3}{7}\div\dfrac{3}{7}\right)+2019\) 

\(=1\times1+2019\) 

\(=2019\)

`@` `\text {Ans}`

`\downarrow`

`69 \times 36 - 38 \times 18`

`= 69 \times 2 \times 18 - 38 \times 18`

`= 18 \times (69 \times 2 - 38)`

`= 18 \times (138 - 38)`

`= 18 \times 100`

`=1800`

=18(69*2-38)

=18*100=1800

 = 2600

chi tiết giúp mk nha

\(26.17+38.26+26.44+26=26\left(17+38+44+1\right)=26.100=2600\)

45 x 38 + 45 x 63 - 45

=45 x 38 + 45 x 63 -45 x 1

=45 x (38+63-1)

=45 x 100

=4500

45x38+45x63-45

=45x(38+63-1)

=45x100

=4500

\(45.38+45.63-45\)

\(=45.38+45.63-45.1\)

\(=45\left(38+63-1\right)\)

\(=45.100=4500\)

Chúc bạn học tốt

\(=46\left(17+38+1+44\right)\)

\(=4600\)

215(12 + 38) = 215.50 = 10750

3450(15 - 5) = 3450.10 = 34500

215(12 + 38) = 215.50 = 10750

3450(15 - 5) = 3450.10 = 34500