=(1637+1233)-(1234+1466)

=2870-2700

=170

a) 19,17x25x4=19,17(25x4)=19,17x100=1917

b)1,79x(8x125)=1,79x1000=1790

chúc bạn học tốt

a, 5 x 4 x 2 x 25

= (5 x 2) x (4 x 25)

= 10 x 100

= 1 000

\(5\times4\times2\times25\)

\(=\left(4\times25\right)\times\left(5\times2\right)\)

\(=100\times10\)

\(=1000\)

a,5 x 4 x 2 x 25                                                                                           = (5 x 2) x ( 4 x 25)                                                                                    =   10    x     100                                                                                                 1 000

giúp mik nha

pls

kh bt làm

= (2/5 x 5/6) x (3/4 : 3/4)
= 2/6 x 1
= 2/6
= 1/3

thank you Tú Cường Trần

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

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

`= 4/7 xx 1`

`= 4/7`

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

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

`#3107.101107`

b)

\(0,5\times\dfrac{3}{4}-\dfrac{1}{2}\times\dfrac{1}{4}\\ =\dfrac{1}{2}\times\dfrac{3}{4}-\dfrac{1}{2}\times\dfrac{1}{4}\\ =\dfrac{1}{2}\times\left(\dfrac{3}{4}-\dfrac{1}{4}\right)\\=\dfrac{1}{2}\times\dfrac{1}{2}\\ =\dfrac{1}{4}\)

=964x10=9640

\(=964\times\left(4+7+1-2\right)\\ =964\times10\\ =9640\)

=964×4+964×7+964×1-964×2.

=964×(4+7+1-2)

=964×10

=9640

1245 x 2 + 3 x 1245 + 1245 x 4 + 1245

= 1245 x 2 + 3 x 1245 + 1245 x 4 + 1245 x 1

= 1245 x (2 + 3 + 4 + 1)

= 1245 x 10

= 12450

\(\frac{2}{3}\times\frac{3}{4}\times\frac{4}{5}\times\frac{5}{6}\)

\(=\frac{2\times3\times4\times5}{3\times4\times5\times6}\)

\(=\frac{2}{6}\)

\(=\frac{1}{3}\)

??????

1/3 nhé