bài 1

A)37/60

B)13/45

C)1/4

bài 2

a)42/25:y/5=5/6

y=10,08

b)27/y:9/4=3/7

y=28

a) 3/4*41/24=41/32

B)  y=4/7:3/5

y=20/21

a)3/4 × (5/6 + 7/8)

=3/4 × 41/24

=41/32

b)3/5 × y=4/7

  y=4/7:3/5

          y=20/21

a) y + 3/7 x 21/9 = 5

      y + 3/7 x 7/3 = 5

      y + 1             = 5

            y             = 4

b) y  x 3/5 - 1/2 = 4/5

    y x 3/5          = 4/5 + 1/2

    y x 3/5          = 13/10

    y                   = 13/6

c) 9/8 - y + 2/5 = 1/4

            y - 2/5  = 9 /8 - 1/4

            y - 2/5  = 7/8

                   y   = 51/40 

d) y - 6/5 : 2/3 = 5/6

    y - 9/5         = 5/6

          y           = 79/30

e) y : 7/8 + 3/4 = 7/4

    y : 7/8          = 1

          y            = 7/8

\(y+\frac{3}{7}\times\frac{21}{9}=5\)

\(y+\frac{3}{7}\times\frac{7}{3}=5\)

\(y+1=5\)

\(\Rightarrow y=4\)

Mk trả lời thiếu, chờ 1 lát

a) 3,7 x y + 5,28 = 14,9

3,7 x y= 9,62

y = 9,62 : 3,7

y = 2,6

1x2x3x4x5x6x7x8x9

2x3x4x5x6x7x8x9x10

=1/10

b)1/2*2/3*3/4*4/5*5/6*6/7*7/8*8/9*9/10

=1x2x3x4x5x6x7x8x9

  2x3x4x5x6x7x8x9x10

= 1

  10

A) 137/ 12

B) 4

C) 5

b, 3/5 + 4/7 + 2/8 + 10/25 + 9/21 + 28/16

= 3/5 + 4/7 + 2/8 + 2/5 + 3/7 + 14/8

= (3/5 + 2/5) + ( 4/7 + 3/7) + ( 2/8 + 14/8)

= 1 + 1 + 7/4

= 2 + 7/4 = 15/4

c , 8/7 + 7/6 + 5/8 + 10/12 + 24/28 + 6/16 

= c , 8/7 + 7/6 + 5/8 + 5/6 + 6/7 + 1/2

= (8/7 + 6/7) + (7/6 + 5/6) + 5/8 + 1/2

= 14/7 + 12/6 + 5/8 + 1/2

= 2 + 2 + 5/8 + 1/2

= 4 + 9/8 = 41/8

2/3 + 7/1 = 2/3 + 7 = 2/3 + 21/3 = 23/3

25/48 + 11/24 = 25/48 + 22/48 = 47/48

5/7 + 3/8 = 40/56 + 21/56 = 61/56

15/24 + 12/6 = 5/8 + 2 = 5/8 + 16/8 = 21/8

5/6 + 4/3 = 5/6 + 8/6 = 13/6

3/8 + 7/12 = 9/24 + 14/24 = 23/24

= 23/3

= 47/48

=61/56

=21/8

=13/6

= 23/24

a: \(\dfrac{1}{8}\cdot\dfrac{4}{5}:\dfrac{3}{5}=\dfrac{1}{10}\cdot\dfrac{5}{3}=\dfrac{1}{2\cdot3}=\dfrac{1}{6}\)

b: \(=\dfrac{8-3}{12}\cdot\dfrac{6}{5}=\dfrac{6}{12}=\dfrac{1}{2}\)

c: \(=\dfrac{24}{35}:\dfrac{32}{35}=\dfrac{3}{4}\)

d: =63/21+15/21-7/21=71/21

a \(\dfrac{1}{8}\times\dfrac{4}{5}\times\dfrac{10}{6}=\dfrac{1}{6}\)

b \(\left(\dfrac{8}{12}-\dfrac{3}{12}\right)\times\dfrac{6}{5}=\dfrac{5}{12}\times\dfrac{6}{5}=\dfrac{1}{2}\)

c \(\dfrac{24}{35}:\dfrac{32}{35}=\dfrac{24}{35}\times\dfrac{35}{32}=\dfrac{3}{4}\)

d \(\dfrac{63}{21}+\dfrac{15}{21}-\dfrac{7}{21}=\dfrac{71}{21}\)

`4/7+4`

`=4/7+4/1`

`=4/7+28/7`

`=32/7`

__

`3+6/11`

`=33/11+6/11`

`=39/11`

__

`3-5/7`

`=3/1-5/7`

`=21/7-5/7`

`=16/7`

__

`21/9-2`

`=21/9-18/9`

`=3/9`

`=1/3`

__

`15/24+2`

`=15/24+48/24`

`=63/24`

`=21/16`

__

`63/45-20/25`

`=63/45-4/5`

`=63/45-36/45`

`=27/45`

`=9/15`

__

`3/4-2/8`

`=3/4-1/4`

`=2/4`

__

`6/7-5/8`

`=48/56-35/56`

`=13/56`

__

`37/45-5/9`

`=37/45-25/45`

`=12/45`

`=4/15`

__

`46/39-11/13`

`=46/39-33/39`

`=13/39`

`=1/2`

__

`5/12+3/4+1/3`

`=5/12+9/12+4/12`

`=14/12+4/12`

`=18/12`

`=3/2`

__

`1/2+3/7+11/14`

`=7/14+6/14+11/14`

`=13/14+11/14`

`=24/14`

`=12/7`

__

`7/10-(1/5+1/4)`

`=7/10-(4/20+5/20)`

`=7/10-9/20`

`=14/20-9/20`

`=5/20`

`=1/4`

__

`15/4-2/3-3/4`

`=(15/4-3/4)-2/3`

`=12/4-2/3`

`=3-2/3`

`=9/3-2/3`

`=7/3`