Question

Tính bằng cách thuận tiện nhất 2/5 x 4/7 + 3/5 x 4/7

Answer 1

`2/5 xx 4/7 + 3/5 xx 4/7`

`= 4/7 xx (2/5 + 3/5)`

`= 4/7 xx 1`

`= 4/7`

Answer 2

\(\dfrac{2}{5}\times\dfrac{4}{7}+\dfrac{3}{5}\times\dfrac{4}{7}=\left(\dfrac{2}{5}+\dfrac{3}{5}\right)\times\dfrac{4}{7}=\dfrac{5}{5}\times\dfrac{4}{7}=1\times\dfrac{4}{7}=\dfrac{4}{7}\)

Answer 3

\(=\dfrac{4}{7}\times\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=\dfrac{4}{7}\)

Answer 4

`2/5xx4/7+3/5xx4/7`

`=(2/5+3/5)xx4/7`

`=1xx4/7`

`=4/7`

`@An`

Answer 5

(2/5 + 3/5) x 4/7
= 1 x 4/7
= 4/7

Answer 6

\(\dfrac{4}{7}\times\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=\dfrac{4}{7}\times\dfrac{5}{5}=\dfrac{4}{7}\times1=\dfrac{4}{7}\)

Answer 7

\(\dfrac{4}{7}\left(\dfrac{2}{5}+\dfrac{3}{5}\right)=\dfrac{4}{7}\times\dfrac{5}{5}=\dfrac{4}{7}\times1=\dfrac{4}{7}\)

Answer 8

4/7 x ( 2/5 + 3/5)=
4/7 x        5/5     = 4/7 x 1 = 4/7

Answer 9

\(\dfrac{2}{5}\times\dfrac{4}{7}+\dfrac{3}{5}\times\dfrac{4}{7}\)

\(=\dfrac{4}{7}\times\left(\dfrac{2}{5}+\dfrac{3}{5}\right)\)

\(=\dfrac{4}{7}\times\dfrac{5}{5}=\dfrac{4}{7}\)

Answer 10

=4/7x(2/5+3/5)=4/7x1=4/7