Bài 1

a) 3 2/5 - 1/2

= 17/5 - 1/2

= 34/10 - 5/10

= 29/10

b) 4/5 + 1/5 × 3/4

= 4/5 + 3/20

= 16/20 + 3/20

= 19/20

c) 3 1/2 × 1 1/7

= 7/2 × 8/7

= 4

d) 4 1/6 : 2 1/3

= 25/6 : 7/3

= 25/14

Bài 2

a) 3 × 1/2 + 1/4 × 1/3

= 3/2 + 1/12

= 18/12 + 1/12

= 19/12

b) 1 4/5 - 2/3 : 2 1/3

= 9/5 - 2/3 : 7/3

= 9/5 - 2/7

= 63/35 - 10/35

= 53/35

Bài 1

a) 3 2/5 - 1/2

= 17/5 - 1/2

= 34/10 - 5/10

= 29/10

b) 4/5 + 1/5 × 3/4

= 4/5 + 3/20

= 16/20 + 3/20

= 19/20

c) 3 1/2 × 1 1/7

= 7/2 × 8/7

= 4

d) 4 1/6 : 2 1/3

= 25/6 : 7/3

= 25/14

bủh

a: =>x-2/5=3/4:1/3=3/4*3=9/4

=>x=9/4+2/5=45/20+8/20=53/20

b: =>x-2/3=7/3:4/5=7/3*5/4=35/12

=>x=35/12+2/3=43/12

c: 1/3(x-2/5)=4/5

=>x-2/5=4/5*3=12/5

=>x=12/5+2/5=14/5

d: =>2/3x-1/3-1/4x+1/10=7/3

=>5/12x-7/30=7/3

=>5/12x=7/3+7/30=77/30

=>x=77/30:5/12=154/25

e: \(\Leftrightarrow x\cdot\dfrac{3}{7}-\dfrac{2}{7}+\dfrac{1}{2}-\dfrac{5}{4}x+\dfrac{5}{2}=0\)

=>\(x\cdot\dfrac{-23}{28}=\dfrac{2}{7}-3=\dfrac{-19}{7}\)

=>x=19/7:23/28=76/23

f: =>1/2x-3/2+1/3x-4/3+1/4x-5/4=1/5

=>13/12x=1/5+3/2+4/3+5/4=257/60

=>x=257/65

i: =>x^2-2/5x-x^2-2x+11/4=4/3

=>-12/5x=4/3-11/4=-17/12

=>x=17/12:12/5=85/144

a: =3^3+4+7=3^14

b: =4^(3+4-2)=4^5

c: =2^(8+2-4)=2^6

d: =5^(7+3-4)=5^6

a. 1/240 : 43/60 = 1/172

b. 59/60 x 22/15 = 649/450

1/172

649/450

1/172

649/450

                                                       ngan:3

`x + 2 3/4 = 5 2/3`

`=> x + 11/4 = 17/3`

`=> x= 17/3 -11/4`

`=>x=35/12`

__

`x - 1 4/5 = 3 2/7`

`=> x- 9/5 = 23/7`

`=> x= 23/7 +9/5`

`=>x=178/35`

__

`x xx 3 1/2 =4 3/4`

`=> x xx 7/2 =19/4`

`=> x= 19/4 : 7/2`

`=> x= 19/4 xx 2/7`

`=> x= 19/14`

__

`x : 2 2/3 = 4 1/3`

`=> x : 8/3 = 13/3`

`=> x= 13/3 xx 8/3`

`=>x=104/9`

a: =>x+11/4=17/3

=>x=17/3-11/4=68/12-33/12=35/12

b: =>x-9/5=23/7

=>x=23/7+9/5=178/35

c: =>x*7/2=4,75

=>x=19/4:7/2=19/14

d: =>x:8/3=13/3

=>x=13/3*8/3=104/9

a) \(x+2\dfrac{3}{4}=5\dfrac{2}{3}\) 

    \(x+\dfrac{11}{4}=\dfrac{17}{3}\) 

              \(x=\dfrac{17}{3}-\dfrac{11}{4}\) 

               \(x=\dfrac{35}{12}\) 

b) \(x-1\dfrac{4}{5}=3\dfrac{2}{7}\) 

      \(x-\dfrac{9}{5}=\dfrac{23}{7}\) 

              \(x=\dfrac{23}{7}+\dfrac{9}{5}\) 

              \(x=\dfrac{178}{35}\) 

c) \(x\times3\dfrac{1}{2}=4\dfrac{3}{4}\) 

    \(x\times\dfrac{7}{2}=\dfrac{19}{4}\) 

            \(x=\dfrac{19}{4}\div\dfrac{7}{2}\) 

            \(x=\dfrac{19}{14}\) 

d) \(x\div2\dfrac{2}{3}=4\dfrac{1}{3}\) 

    \(x\div\dfrac{8}{3}=\dfrac{13}{3}\) 

            \(x=\dfrac{13}{3}\times\dfrac{8}{3}\) 

            \(x=\dfrac{104}{9}\)

a) \(...=x+\dfrac{11}{3}=\dfrac{17}{3}\Rightarrow x=\dfrac{17}{3}-\dfrac{11}{3}=\dfrac{6}{3}=2\)

b) \(...\Rightarrow x-\dfrac{9}{5}=\dfrac{23}{7}\Rightarrow x=\dfrac{23}{7}+\dfrac{9}{5}=\dfrac{115}{35}+\dfrac{36}{35}=\dfrac{151}{35}\)

c) \(...\Rightarrow x.\dfrac{7}{2}=\dfrac{19}{4}\Rightarrow x=\dfrac{19}{4}:\dfrac{7}{2}\Rightarrow x=\dfrac{19}{4}.\dfrac{2}{7}=\dfrac{19}{14}\)

d) \(...\Rightarrow x:\dfrac{8}{3}=\dfrac{13}{3}\Rightarrow x=\dfrac{13}{3}.\dfrac{8}{3}=\dfrac{124}{9}\)

a) 35/12

b) 178/35

c) 19/14

d) 104/9

a) 2 x 2 = 4              3 x 3 = 9

2 x 4 = 8              3 x 5 = 15

2 x 6 = 12              3 x 7 = 21

2 x 8 = 16              3 x 9 = 27

4 x 4 = 16              5 x 5 = 25

4 x 2 = 8              5 x 7 = 35

4 x 6 = 24              5 x 9 = 45

4 x 8 = 32              5 x 3 = 15

b) 200 x 4 = 800              300 x 2 = 600

200 x 2 = 400             300 x 3 = 900

400 x 2 = 800             500 x 1 = 500

100 x 4 = 400             100 x 3 = 300

Trả lời 1 câu thôi nhé em 100 nhân 4 bằng 400 nhá em

a) 2 x 2 =4 ......              3 x 3 = ..9....

2 x 4 = ....8..              3 x 5 = ...15...

2 x 6 = ....12..              3 x 7 = .21.....

2 x 8 = ..16....              3 x 9 = ..27....

4 x 4 = ...16...              5 x 5 = ...25...

4 x 2 = ...8...              5 x 7 = ..35....

4 x 6 = .....24.              5 x 9 = .45.....

4 x 8 = ..32....              5 x 3 = .15.....

b) 200 x 4 = 800......              300 x 2 =600 ......

200 x 2 = ..400....             300 x 3 = 900......

400 x 2 = .....800.             500 x 1 = ..500....

100 x 4 = ....400..             100 x 3 = .300.....

giúp mình đi mà

a: 3/7x4/5=12/35

2/5+3/4=8/20+15/20=23/20

b: 2/5:4=2/20=1/10

1/4+2=9/4

c: 2/5:2/3=3/5

2/3-3/8=16/24-9/24=7/24

Phương pháp giải:

 - Muốn tìm số bị trừ ta lấy hiệu cộng với số trừ.

 - Muốn tìm số bị chia ta lấy thương nhân với số chia. 

Lời giải chi tiết:

a)

● x − 4 = 2

    x = 2 + 4

    x = 6

● x : 4 = 2

    x = 2 × 4

    x = 8

b)

● x − 5 = 4

    x = 4 + 5

    x = 9

● x : 5 = 4

    x = 4 × 5

    x = 20

c)

● x − 3 = 3

    x = 3 + 3

    x = 6

● x : 3 = 3

    x = 3 × 3

    x = 9