31/23-(7/32+8/23) =31/23-417/736=25/32

31/23-(7/32+8/23)

=31/23-7/32-8/23

=(31/23-8/23)-7/32

=23/23-7/32

=1-7/32=32/32-7/32=25/32

31 / 23 - ( 7 / 23 + 8 / 23 ) = 31 / 23 - 7 / 23 - 8 / 23 

                                            = ( 31 / 23 + ( -8 ) / 23 ) + ( - 7 ) / 23

                                            =   23 / 23 + ( -7 ) / 23

                                            =  16 / 23

a: =-12/20+5/20-6/20

=-13/20

b: =10/50-45/50-14/50

=-49/50

c: =31/23-7/32-8/23=1-7/32=25/32

`a)-3/5 + 1/4 + -3/10= (-12)/20 + 5/20 + (-6)/20 = -13/20` 

`b)1/5 + -9/10 + (-7/25)= 10/50 + (-45)/50 + (-14)/50 = (-49)/50`

`c)31/23 - ( 7/32 + 8/23 )=  31/23 - 417/736 =992/736 - 417/736  =  575/736=25/32  `

`a,`

`31/23-(7/32+8/23)`

`=31/23-7/32-8/23`

`=(31/23-8/23)-7/32`

`=1-7/32=25/32`

`b,`

`38/45-(8/45-17/51-3/11)`

`=38/45-8/45+17/51+3/11`

`= (38/45-8/45)+17/51+3/11`

`=2/3+17/51+3/11`

`=1+3/11=14/11`

`c,`

`(1/3+12/67+13/41)-(79/67-28/41)`

`= 1/3+12/67+13/41-79/67+28/41`

`= 1/3+(12/67-79/67)+(13/41+28/41)`

`= 1/3+(-1)+1=1/3+(-1+1)=1/3+0=1/3`

`d,`

`1/5+(-1/6)+1/7+(-1/8)+1/9+1/8+(-1/7)+1/6+(-1/5)`

`= (1/5+ -1/5)+(-1/6+1/6)+(1/7+ -1/7)+(-1/8 +1/8)+1/9`

`= 0+0+0+0+1/9=1/9 .`

107/96

chúc em học giỏi ^_^

minh k biet xin loi ban nha!

minh k biet xin loi ban nha!

minh k biet xin loi ban nha!

minh k biet xin loi ban nha!

Ai co the giai can than duoc k

a: =1/8-1/8+2/5=2/5

b: =(-1/15-14/15)+(23/27+31/27)=2-1=1

c: \(=\dfrac{3}{7}\left(\dfrac{22}{21}+\dfrac{5}{21}+\dfrac{15}{21}\right)=\dfrac{3}{7}\cdot2=\dfrac{6}{7}\)

d: \(=\dfrac{-8}{9}\cdot\dfrac{3}{2}+\dfrac{1}{9}\cdot\dfrac{-3}{2}=-\dfrac{3}{2}\)

\(49\dfrac{8}{23}-\left(5\dfrac{7}{32}+14\dfrac{8}{23}\right)=49\dfrac{8}{23}-5\dfrac{7}{32}-14\dfrac{8}{23}=\left(49\dfrac{8}{23}-14\dfrac{8}{23}\right)-5\dfrac{7}{32}=35-5\dfrac{7}{32}=\dfrac{953}{32}\)