\(-\frac{1}{2}+\frac{2}{3}-\frac{3}{4}+\frac{4}{5}\)

\(=\left(-\frac{1}{2}-\frac{3}{4}\right)+\left(\frac{2}{3}+\frac{4}{5}\right)\)

\(=\left(-\frac{2}{4}-\frac{3}{4}\right)+\left(\frac{10}{15}+\frac{12}{15}\right)\)

\(=\left(\frac{-2-3}{4}\right)+\left(\frac{10+12}{15}\right)\)

\(=\left(\frac{-5}{4}\right)+\left(\frac{22}{15}\right)\)

\(=\frac{-75}{60}+\frac{88}{60}\)

\(=\frac{-75+88}{60}\)

\(=\frac{13}{60}\)

Mình ghi rõ từng chi tiết rồi nha , chúc bạn học tốt !!! 

-1/2+ 2/3 - 3/4 + 4/5

= (-1/2-3/4) + (2/3+4/5)

= -5/4 + 22/15

= 13/60

Thực hiện phép tính ( bằng cách hợp lí nếu có thể ) 

A. 2/3 - (- 1/4)+3/5-(+7/45)-(-5/9)+1/12+1/39 

B. 6.(-2/3)^2 - 3(-2/3)^2 - 2 : (-3/2)+4

\(-\frac{3}{5}.\frac{11}{7}+\frac{3}{-5}.\frac{4}{7}+\frac{23}{7}\)

\(=\frac{-3}{5}\left(\frac{11}{7}+\frac{4}{7}\right)+\frac{23}{7}\)

\(=\frac{-3}{5}.\frac{15}{7}+\frac{23}{7}\)

\(=\frac{-9}{7}+\frac{23}{7}=2\)

\(\Rightarrow A=\left(\frac{27}{23}-\frac{4}{23}\right)+\left(\frac{5}{21}+\frac{16}{21}\right)+\frac{1}{2}\)

\(\Rightarrow A=1+1+\frac{1}{2}\)

\(\Rightarrow A=\frac{5}{2}\)

tíc mình nha

A=1+1+1/2

A=5/2

=5/2 nhé

a: \(=23\cdot100+300=2600\)

b: \(=300:\left(4+6\right)-25=30-25=5\)

a) 23.(16+84)+300=23.100+300=2600

b)300:(4+6)-25=300:10-25=5 

= 280 :  [25 + ( 30 - 3 mũ 3 ) ]

= 280 :  [ 25 + ( 30 - 27 ) ]

=  280 : ( 25 + 3 )

= 280 : 28

=10  

= [ 60/90 - ( 12/15 + 10/15) ] : 6/5

= ( 2/3 - 22/15 ) x 5/6

= ( 10/15 - 22/15 ) x 5/6

= -12/15 x 5/6

= -60/90

= -2/3

( 15/10 x 4/9 - ( 4/5 + 2/3 )) : 6/5

( 15/10 x 4/9 - ( 12/15 + 10/15 )) : 6/5

(30/45 - 66/45 ) : 6/5

-12/15 : 6/5 ( đã rút gọn -36/45 = -12/15 )

-2/3

k mk na <3