a) Cách 1 : (3/4 + 1/2) x 5/7

               = 5/4 x 5/7

                = 25/28

Cách 2 : (3/4 + 1/2) x 5/7

           = 3/4 x 5/7 + 1/2 x 5/7

            = 15/28 + 5/14

            = 25/28

b) Cách 1 : 5/7 x 13/21 + 2/7 x 13/21

= 65/147 + 26/147

= 13/21

Cách 2 : 5/7 x 13/21 + 2/7 x 13/21

= (5/7 + 2/7) x 13/21

= 1 x 13/21

= 13/21

câu c tự làm

8 /15 :2/3+7/15:2/3 =                                              tính bằng 2 cách nhé các bạn

Cách 1:6/8+4/8+5/7=10/8*5/7=50/56=25/28

Cách 2 :3/4*5/7+1/2*
5/7=15/28+10/28=25/28

Cái này thầy tôi đã chữa yên tâm

`(1/3 + 1/5) xx 1/4`

`= ( 5/15 + 3/15) xx 1/4`

`= 8/15 xx 1/4`

`= 8/60`

`= 2/15`

__

`(1/3 + 1/5) xx 1/4`

`= 1/3 xx 1/4 + 1/5 xx 1/4`

`= 1/12 +1/20`

`=2/15`

\(C_1:\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{4}\times\dfrac{1}{3}+\dfrac{1}{4}\times\dfrac{1}{5}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{2}{15}\)

\(C_2:\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8\times1}{15\times4}=\dfrac{8}{60}=\dfrac{2}{15}\)

Cách 1:

\(\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\left(\dfrac{5}{15}+\dfrac{3}{15}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8}{60}=\dfrac{2}{15}\)

Cách 2:

\(\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{3}\times\dfrac{1}{4}+\dfrac{1}{5}\times\dfrac{1}{4}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{5}{60}+\dfrac{3}{60}=\dfrac{8}{60}=\dfrac{2}{15}\)

\(a,\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{8}{15}\times\dfrac{1}{4}=\dfrac{8}{60}=\dfrac{2}{15}\)

\(\left(\dfrac{1}{3}+\dfrac{1}{5}\right)\times\dfrac{1}{4}=\dfrac{1}{3}\times\dfrac{1}{4}+\dfrac{1}{5}\times\dfrac{1}{4}=\dfrac{1}{12}+\dfrac{1}{20}=\dfrac{20}{240}+\dfrac{12}{240}=\dfrac{32}{240}=\dfrac{2}{15}\)

\(b,\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{2}{5}\times\left(\dfrac{3}{7}+\dfrac{4}{7}\right)=\dfrac{2}{5}\times1=\dfrac{2}{5}\)

\(\dfrac{2}{5}\times\dfrac{3}{7}+\dfrac{2}{5}\times\dfrac{4}{7}=\dfrac{6}{35}+\dfrac{8}{35}=\dfrac{14}{35}=\dfrac{2}{5}\)

trả lời nhanh nha! trả lời trong tối hôm nay 19/3/2023 ạ

C1 : `a)(1/3+1/5)xx1/4`

`=(5/15+3/15)xx1/4`

`=8/15xx1/4`

`=8/60`

`=2/15`

__

C2: `a)(1/3+1/5)xx1/4`

`=1/3xx1/4+1/5xx1/4`

`=1/12+1/20`

`=5/60+3/60`

`=8/60`

`=2/15`

_________________

C1: `b)2/5xx3/7+2/5xx4/7`

`=6/35+8/35`

`=14/35`

`=2/5`

__

C2: `b)2/5xx3/7+2/5xx4/7`

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

`=2/5xx7/7`

`=2/5xx1`

`=2/5`

5,5 + \(\dfrac{3}{4}\) - 5 + \(\dfrac{1}{4}\)

(5,5 - 5) + (\(\dfrac{3}{4}\) + \(\dfrac{1}{4}\))

= 0,5  + 1

= 1,5 

\(\dfrac{5}{2}\) x  \(\dfrac{2}{3}\) + \(\dfrac{1}{4}\) : \(\dfrac{3}{2}\)

= \(\dfrac{5}{2}\) x \(\dfrac{2}{3}\) + \(\dfrac{1}{4}\) x \(\dfrac{2}{3}\)

=  (\(\dfrac{5}{2}\) + \(\dfrac{1}{4}\)) x \(\dfrac{2}{3}\)

= (\(\dfrac{10}{4}\) + \(\dfrac{1}{4}\)) x \(\dfrac{2}{3}\)

= \(\dfrac{11}{4}\) x \(\dfrac{2}{3}\)

= \(\dfrac{11}{6}\) 

Tính \(x\): 

  435  - [\(x\) + 16] = 425 : 17

  435 - [\(x\) + 16] = 25

          [\(x\) + 16] = 435 - 25

           \(x\) + 16 = 410

           \(x\)        = 410 - 16

          \(x\)         = 394

\(x\) x \(\dfrac{1}{4}\) - \(\dfrac{3}{4}\) = 6 : \(\dfrac{3}{4}\)

\(x\) \(\times\) \(\dfrac{1}{4}\) - \(\dfrac{3}{4}\) = 6 x \(\dfrac{4}{3}\)

\(x\) x \(\dfrac{1}{4}\) - \(\dfrac{3}{4}\)  = 8

\(x\) x \(\dfrac{1}{4}\)        = 8 + \(\dfrac{3}{4}\)

\(x\) x \(\dfrac{1}{4}\)        = \(\dfrac{32}{4}\) + \(\dfrac{3}{4}\)

\(x\) x \(\dfrac{1}{4}\)       = \(\dfrac{35}{4}\)

\(x\)              =  \(\dfrac{35}{4}\) : \(\dfrac{1}{4}\)

\(x\)              = \(\dfrac{35}{4}\) x 4

\(x\)             = 35

a: \(=\dfrac{2}{3}\cdot\dfrac{4}{5}\cdot\dfrac{5}{6}=\dfrac{2}{3}\cdot\dfrac{2}{3}=\dfrac{4}{9}\)

b: \(=\dfrac{5}{6}\cdot\dfrac{1}{5}=\dfrac{1}{6}\)

a. C1: \(\dfrac{8}{15}.\dfrac{5}{6}=\dfrac{4}{9}\)

C2: \(\dfrac{2}{3}.\dfrac{4}{5}.\dfrac{5}{6}=\dfrac{2.4.5}{3.5.3.2}\)

Triệt tiêu phần giống nhau ở tử và mẫu ta có 

\(=\dfrac{4}{9}\)

b. \(C1:\left(\dfrac{1}{2}+\dfrac{1}{3}\right).\dfrac{1}{5}=\dfrac{5}{6}.\dfrac{1}{5}=\dfrac{1}{6}\)

C2: \(\dfrac{1}{2}.\dfrac{1}{5}+\dfrac{1}{3}.\dfrac{1}{5}=\dfrac{1}{10}+\dfrac{1}{15}=\dfrac{1}{6}\)

Cách 1:

$(\frac{2}{3}\times \frac{4}{5})\times \frac{5}{6}=\frac{8}{15}\times \frac{5}{6}=\frac{8\times 5}{15\times 6}=\frac{2\times 2\times 2\times 5}{3\times 5\times 2\times 3}=\frac{4}{9}$

Cách 2:

$(\frac{2}{3}\times \frac{4}{5})\times \frac{5}{6}=\frac{2}{3}\times (\frac{4}{5}\times \frac{5}{6})=\frac{2}{3}\times \frac{4}{6}=\frac{2\times 4}{3\times 6}=\frac{2\times 4}{3\times 2\times 3}=\frac{4}{9}$

Cách 1:

$(\frac{1}{2}+\frac{1}{3})\times \frac{1}{5}=\left(\frac{3+2}{6}\right)\times \frac{1}{5}=\frac{5}{6}\times \frac{1}{5}=\frac{1}{6}$

Cách 2:

$(\frac{1}{2}+\frac{1}{3})\times \frac{1}{5}=\frac{1}{2}\times \frac{1}{5}+\frac{1}{3}\times \frac{1}{5}=\frac{1}{10}+\frac{1}{15}=\frac{3}{30}+\frac{2}{30}=\frac{5}{30}=\frac{1}{6}$

Giải đấy đủ giúp mình với 

a: =8/15x1/4=2/15

b: \(=\dfrac{5}{3}\cdot\dfrac{4}{5}\cdot\dfrac{6}{7}=\dfrac{24}{21}=\dfrac{8}{7}\)

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

(2/3 x 4/5) x 5/6

=   8/15     x 5/6

=             4/9

(2/3 x 4/5) x 5/6 

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

=        2/3     x 2/3

=              4/9

(1/2 + 1/3) x 1/5

=   5/6        x 1/5

=               1/6

(1/2 + 1/3) x 1/5

= (1/2 x 1/5) + (1/3 x 1/5)

=       1/10    +        1/15

=                 1/6

4A6?

Đây bạn nhé

cách1\(\left(\frac{2}{3}\times\frac{4}{5}\right)\times\frac{5}{6}\)=\(\frac{8}{15}\times\frac{5}{6}\)=\(\frac{4}{9}\)cách2 =\(\left(\frac{2}{3}\times\frac{4}{5}\right)\times\frac{5}{6}\)\(\frac{2}{3}\times\frac{4}{5}\times\frac{5}{6}\)=\(\frac{40}{90}\)=\(\frac{4}{9}\)

cách1\( \left(\frac{1}{2}+\frac{1}{3}\right)\times\frac{1}{5}\)= \(\frac{5}{6}\times\frac{1}{5}\)=\(\frac{1}{6}\)cách2\( \left(\frac{1}{2}+\frac{1}{3}\right)\times\frac{1}{5}\)=\(\frac{1}{2}\times\frac{1}{5}+\frac{1}{3}\times\frac{1}{5}\)=\(\frac{1}{10}+\frac{1}{15}\)=\(\frac{25}{150}\)=\(\frac{1}{6}\)

cách1\(\left(\frac{2}{3}\times\frac{4}{5}\right)\times\frac{5}{6}\)=\(\frac{2}{3}\times\left(\frac{4}{5}\times\frac{5}{6}\right)\)=\(\frac{2}{3}\times\frac{2}{3}\)=\(\frac{4}{9}\) cách 2 \(\left(\frac{2}{3}\times\frac{4}{5}\right)\times\frac{5}{6}\)=\(\frac{2}{3}\times\frac{4}{5}\times\frac{5}{6}\)=\(\frac{2\times4\times5}{3\times5\times6}\)=\(\frac{2\times4\times5}{3\times5\times2\times3}\)=\(\frac{4}{9}\)

cách1\(\left(1\times2+\frac{1}{3}\right)\times\frac{1}{5}\)=\(\frac{7}{3}\times\frac{1}{5}\)=\(\frac{7}{15}\) cách2\(\left(1\times2+\frac{1}{3}\right)\times\frac{1}{5}\)=\(1\times\left(2+\frac{1}{3}\right)\times\frac{1}{5}\)=\(1\times\frac{7}{3}\times\frac{1}{5}\)=\(\frac{7}{3}\times\frac{1}{5}\)=\(\frac{7}{15}\)

/HT\

a) Cách 1

\(\frac{3}{4}\)x \(\frac{1}{2}\)x \(2\)

= \(\frac{3}{8}\)x \(2\)

= \(\frac{3}{4}\)

Cách 2

\(\frac{3}{4}\)x \(\frac{1}{2}\)x \(2\)

= \(\frac{3}{4}\)x \(\left(\frac{1}{2}x2\right)\)

= \(\frac{3}{4}\)x 1

= \(\frac{3}{4}\)

Nhào vô trả lời nhanh và đúng mk k cho!!!

nhanh! nhanh ! nhanh

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