2/3

4

\(\dfrac{13}{15}-\dfrac{1}{5}=\dfrac{13}{15}=\dfrac{3}{15}=\dfrac{10}{15}=\dfrac{2}{3}\)

\(\dfrac{7}{8}\times\dfrac{2}{7}=\dfrac{14}{56}=\dfrac{1}{4}\)

=1/21 nha bạn

= 1/21 đó bn...tích dùm mk nha!!

\(\frac{7}{15}+\frac{2}{10}=\frac{14}{30}+\frac{6}{30}=\frac{20}{30}=\frac{2}{3}\)

\(\frac{8}{3}+\frac{4}{3}=\frac{12}{3}=\frac{4}{1}=4\)

a, \(\frac{7}{15}+\frac{2}{10}=\frac{2}{3}\)

b,\(\frac{8}{3}+\frac{4}{3}=4\)

\(\frac{7}{15}\)\(+\frac{2}{10}\)\(=\frac{2}{3}\)

\(\frac{8}{3}\)\(+\frac{4}{3}\)\(=4\)

\(\dfrac{3}{7}:x=\dfrac{5}{7}\)

      \(x=\dfrac{3}{7}:\dfrac{5}{7}\)

     \(x=\dfrac{3}{7}\times\dfrac{7}{5}\)

     \(x=\dfrac{21}{35}\) 

     \(x=\dfrac{3}{5}\)

\(\dfrac{3}{7}:x=\dfrac{5}{7}\\ x=\dfrac{3}{7}:\dfrac{5}{7}\\ x=\dfrac{3}{5}\)

Vậy `x=3/5`

`@An`

\(\frac{7}{15}+\frac{2}{10}\)

\(=\frac{7}{15}+\frac{1}{5}\)

=\(\frac{7}{15}+\frac{3}{15}\)

=\(\frac{10}{15}\)

=\(\frac{2}{3}\)

\(\frac{7}{15}+\frac{2}{10}\)

\(=\frac{7}{15}+\frac{1}{5}\)

\(=\frac{7}{15}+\frac{3}{15}\)

\(=\frac{10}{15}=\frac{2}{3}\)

\(\frac{7}{5}+\frac{2}{10}=\frac{70}{50}+\frac{10}{50}=\frac{80}{50}=\frac{8}{5}\)\(\frac{8}{5}\)

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

\(=\frac{1\times2\times3}{2\times3\times4}\)

\(=\frac{1}{4}\)

1/2 x 2/3 x 3/4 = 1/3 x 3/4 = 1/4

hok tốt

1/2 . 2/3 . 3/4

= 1/3 . 3/4

= 1/4

\(\frac{2}{3}\)bạn nhé! Nếu cần thì mình sẽ cho bạn cách làm

bang 2/3

bằng 2/3 bạn nhé cho mik nha

= 11/2 nha bn

11/2 bạn nha tk và kb với mk đi

11 / 12 : 1/6 = 11/2 

tk cho mk nha 

hihi <3 

2/5 + 4/5 : 6/5

= 2/5 + 4/5 . 5/6

= 2/5 + 20/30

= 6/15 + 10/15

= 16/15

\(\frac{2}{5}+\frac{4}{5}:\frac{6}{5}=\frac{16}{15}\)

\(\frac{2}{5}+\frac{4}{5}:\frac{6}{5}\)

\(=\frac{2}{5}+\frac{4}{5}\times\frac{5}{6}\)

\(=\frac{2}{5}+\frac{2}{3}\)

\(=\frac{6}{15}+\frac{10}{15}\)

\(=\frac{16}{15}\)