`@` `\text {Ans}`

`\downarrow`

`1/3+6/9+4/5+5/25`

`= 1/3+2/3+4/5+1/5`

`= 1+1`

`= 2`

`4/7*2/5+4/7*3/5-1/7`

`= 4/7*(2/5+3/5)-1/7`

`= 4/7*1-1/7`

`= 4/7-1/7=3/7`

.....................................................

giúp mình  đi

\(\dfrac{3}{7}+\dfrac{5}{7}+1+3+4+\dfrac{2}{7}+\dfrac{4}{7}+2=\left(\dfrac{3}{7}+\dfrac{5}{7}+\dfrac{2}{7}+\dfrac{4}{7}\right)+\left(1+3+4+2\right)=2+10=12\)

3/7+5/7+1+3+5+2/7+4/7+2

=(3/7+5/7+2/7+4/7)+(1+3+5+2)

=2+11

=13

a) \(\dfrac{13}{20}+\dfrac{3}{5}+x=\dfrac{5}{6}\)

\(\Rightarrow\dfrac{5}{4}+x=\dfrac{5}{6}\)

\(\Rightarrow x=\dfrac{5}{6}-\dfrac{5}{4}\)

\(\Rightarrow x=\dfrac{-5}{12}\)

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

\(\Rightarrow x+\dfrac{1}{3}=\dfrac{11}{15}\)

\(\Rightarrow x=\dfrac{11}{15}-\dfrac{1}{3}\)

\(\Rightarrow x=\dfrac{2}{5}\)

c)\(\dfrac{-5}{8}-x=\dfrac{-3}{20}-\dfrac{-1}{6}\)

\(\dfrac{-5}{8}-x=\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-5}{8}-\dfrac{1}{60}\)

\(\Rightarrow x=\dfrac{-77}{120}\)

d) \(\dfrac{3}{5}-x=\dfrac{1}{4}+\dfrac{7}{10}\)

\(\Rightarrow\dfrac{3}{5}-x=\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{3}{5}-\dfrac{19}{20}\)

\(\Rightarrow x=\dfrac{-7}{20}\)

e) \(\dfrac{-3}{7}-x=\dfrac{4}{5}+\dfrac{-2}{3}\)

\(\Rightarrow\dfrac{-3}{7}-x=\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-3}{7}-\dfrac{2}{15}\)

\(\Rightarrow x=\dfrac{-59}{105}\)

g) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)

\(\Rightarrow\dfrac{-5}{6}-x=\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-5}{6}-\dfrac{1}{4}\)

\(\Rightarrow x=\dfrac{-13}{12}\)

35/7 + 18/9= 5+ 2 = 7

\(=\frac{18+3+14}{7}+\frac{8+5+5}{9}=\frac{35}{7}+\frac{18}{9}=5+2=7\)

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