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

a: \(=\dfrac{3\cdot2+5}{10}\cdot\dfrac{4}{5}=\dfrac{11}{10}\cdot\dfrac{4}{5}=\dfrac{44}{50}=\dfrac{22}{25}\)

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

3228

3228 nhé em

thanks

Câu 1:

a. $3\frac{2}{3}+2\frac{1}{2}=(3+2)+(\frac{2}{3}+\frac{1}{2})=5+\frac{7}{6}=6+\frac{1}{6}=6\frac{1}{6}$

b. \(2\frac{1}{2}\times 3\frac{2}{5}=\frac{5}{2}\times \frac{17}{5}=\frac{17}{2}\)

c.

\(3\frac{1}{3}: 4\frac{1}{4}=\frac{10}{3}: \frac{17}{4}=\frac{40}{51}\)

d.

\(3\frac{1}{2}+4\frac{5}{7}-5\frac{5}{14}=(3+4-5)+(\frac{1}{2}+\frac{5}{7}-\frac{5}{14})=2+\frac{6}{7}=2\frac{6}{7}\)

Câu 2:

a. $x\times \frac{2}{7}=\frac{6}{11}$

$x=\frac{6}{11}: \frac{2}{7}=\frac{21}{11}$

b. $x: \frac{3}{2}=\frac{1}{4}$

$x=\frac{1}{4}\times \frac{3}{2}=\frac{3}{8}$

Câu 3:

Coi số lớn là 5 phần thì số bé là 3 phần. Hiệu số phần bằng nhau là:
$5-3=2$ (phần)

Số lớn là: $36:2\times 5=90$

Số bé là: $36:2\times 3=54$

Giải chi tiết tiết hộ mình nhé

Giúp 

c1 :(5/4 + 2/5) : 5/6 = 33/20 : 5/6 = 99/50 

c2 :(5/4 + 2/5) : 5/6 = 5/4 : 5/6 + 2/5 : 5/6 =99/50

c1 : 3/4 x 2/5 - 3/4 x 2/7 = 3/4 x (2/5 - 2/7) = 3/4 x 4/35 = 3/35

c2 : 3/4 x 2/5 - 3/4 x 2/7 = 3/35

c1 : 2/3 : (5/6 x 9/10) = 2/3 : 3/4 = 8/9

c2 : 2/3 : (5/6 x 9/10) = 5/6 : 2/3 x 9/10 : 2/3 = 27/16 * cái này chx chắc:"> quên mất cách lm;-;"" "

\(\dfrac{4}{7}:\dfrac{4}{3}+5:\dfrac{4}{3}=\left(\dfrac{4}{7}+5\right):\dfrac{4}{3}=\dfrac{39}{7}:\dfrac{4}{3}=\dfrac{39}{7}\times\dfrac{3}{4}=\dfrac{117}{28}\)

\(\dfrac{4}{7}:\dfrac{4}{3}+5:\dfrac{4}{3}=\dfrac{3}{7}+\dfrac{15}{4}=\dfrac{12}{28}+\dfrac{105}{28}=\dfrac{117}{28}\)

\(\dfrac{3}{4}\times\dfrac{2}{5}-\dfrac{3}{4}\times\dfrac{2}{7}=\dfrac{3}{4}\times\left(\dfrac{2}{5}-\dfrac{2}{7}\right)=\dfrac{3}{4}\times\dfrac{4}{35}=\dfrac{12}{140}=\dfrac{3}{35}\)

\(\dfrac{3}{4}\times\dfrac{2}{5}-\dfrac{3}{4}\times\dfrac{2}{7}=\dfrac{3}{10}-\dfrac{3}{14}=\dfrac{42}{140}-\dfrac{30}{140}=\dfrac{12}{140}=\dfrac{3}{35}\)

\(\left(\dfrac{2}{3}-\dfrac{4}{7}\right)\times\dfrac{2}{5}=\dfrac{2}{21}\times\dfrac{2}{5}=\dfrac{4}{105}\)

\(\left(\dfrac{2}{3}-\dfrac{4}{7}\right)\times\dfrac{2}{5}=\dfrac{2}{3}\times\dfrac{2}{5}-\dfrac{4}{7}\times\dfrac{2}{5}=\dfrac{4}{15}-\dfrac{8}{35}=\dfrac{140}{525}-\dfrac{120}{525}=\dfrac{20}{525}=\dfrac{4}{105}\)

#YVA

4/7:4/3+5:4/3

= 3/7 + 15/4

=4 5/28

4/7:4/3+5:4/3

= (4/7+5) x 3/4

=4 5/28

3/4x2/5-3/4x2/7

=3/10 - 3/14

=3/35

3/4x2/5-3/4x2/7

=3/4x(2/5-2/7)

=3/35

(2/3-4/7)x2/5

=2/21x2/5

=4/105

(2/3-4/7)x2/5

=2/3x2/5-4/7x2/5

=4/105

Tham khảo nhé bạn :))

bbbbb

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

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

A = 1 + 1 + 1

A = 3

B = ( \(\dfrac{3}{4}\) + \(\dfrac{5}{7}\)+ \(\dfrac{16}{64}\)+ \(\dfrac{2}{7}\)) - 2

B = ( \(\dfrac{3}{4}\)+ \(\dfrac{1}{4}\)) + ( \(\dfrac{5}{7}\)+ \(\dfrac{2}{7}\)) - 2

B = 1 + 1 - 2

B = 2 - 2

B = 0

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

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

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

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

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

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`