a: \(=\dfrac{4}{5}+\dfrac{1}{5}\cdot\dfrac{5}{2}=\dfrac{4}{5}+\dfrac{1}{2}=\dfrac{8}{10}+\dfrac{5}{10}=\dfrac{13}{10}\)

b: \(=\dfrac{5}{6}\cdot\dfrac{1}{5}\cdot\dfrac{2}{5}=\dfrac{1}{6}\cdot\dfrac{2}{5}=\dfrac{2}{30}=\dfrac{1}{15}\)

a) \(=\dfrac{13}{10}\)

b) \(=\dfrac{1}{15}\)

a)\(\dfrac{13}{10}\)

b)\(\dfrac{1}{15}\)

a: =25/30+12/30=37/30

b: =24/20-15/20=9/20

c: =36/48=3/4

d: =8/17x1/6=8/102=4/51

a) \(\dfrac{25}{30}+\dfrac{12}{30}=\dfrac{37}{30}\)

b) \(\dfrac{24}{20}-\dfrac{15}{20}=\dfrac{9}{20}\)

c) \(\dfrac{36}{48}=\dfrac{3}{4}\)

d) \(\dfrac{8}{17}\times\dfrac{1}{6}=\dfrac{8}{102}=\dfrac{4}{51}\)

\(\dfrac{5}{6}+\dfrac{2}{5}=\dfrac{25}{30}+\dfrac{12}{30}=\dfrac{37}{30}\)

\(\dfrac{6}{5}-\dfrac{3}{4}=\dfrac{24}{20}-\dfrac{15}{20}=\dfrac{9}{20}\)

\(\dfrac{9}{16}\times\dfrac{4}{3}=\dfrac{36}{48}\)

\(\dfrac{8}{17}:6=\dfrac{8}{102}\)

a: =5/30-12/30=-7/30

b: =-2-5/8=-16/8-5/8=-21/8

c: =6/13-14/39=18/39-14/39=4/39

d: =18/30-25/30=-7/30

e: =-5/9+5/12=-20/36+15/36=-5/36

a) \(\dfrac{-7}{30}\)

b) \(\dfrac{-21}{8}\)

c) \(\dfrac{-7}{30}\)

d) \(\dfrac{-5}{36}\)

\(a,\dfrac{1}{6}+\dfrac{-2}{5}=\dfrac{5}{30}+\dfrac{-12}{30}=\dfrac{-7}{30}\\ b,\left(-2\right)+\dfrac{-5}{8}=\dfrac{-16}{8}+\dfrac{-5}{8}=\dfrac{-21}{8}\\ c,\dfrac{6}{13}+\dfrac{-14}{39}=\dfrac{18}{39}+\dfrac{-14}{39}=\dfrac{4}{39}\\ d,\dfrac{3}{5}-\dfrac{5}{6}=\dfrac{18}{30}-\dfrac{25}{30}=\dfrac{-7}{30}\\ e,\dfrac{-5}{9}-\dfrac{-5}{12}=\dfrac{-20}{36}-\dfrac{-15}{36}=\dfrac{-5}{36}\)

\(a,\frac{5}{1.3}+\frac{5}{3.5}+\frac{5}{5.7}+...+\frac{5}{43.45}=\frac{5}{2}\left(\frac{2}{1.3}+\frac{2}{3.5}+\frac{2}{5.7}+...+\frac{2}{43.45}\right)=\frac{5}{3}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{43}-\frac{1}{45}\right)=\frac{5}{3}.\frac{44}{45}=\frac{44}{27}\)

A) \(\frac{7}{8}-\frac{5}{12}=\frac{84}{96}-\frac{40}{96}=\frac{44}{96}=\frac{11}{24}\)

B)\(\frac{8}{15}-\frac{2}{5}=\frac{8}{15}-\frac{6}{15}=\frac{2}{15}\)

C)\(\frac{5}{6}-\frac{3}{10}=\frac{50}{60}-\frac{18}{60}=\frac{32}{60}=\frac{8}{15}\)

D)\(\frac{7}{10}-\frac{1}{5}=\frac{7}{10}-\frac{2}{10}=\frac{5}{10}=\frac{1}{2}\)

2)A)\(\frac{5}{10}-\frac{2}{15}=\frac{1}{2}-\frac{2}{15}=\frac{15}{30}-\frac{4}{30}=\frac{11}{30}\)

B)\(\frac{5}{20}-\frac{1}{6}=\frac{1}{4}-\frac{1}{6}=\frac{6}{24}-\frac{4}{24}=\frac{2}{24}=\frac{1}{12}\)

C)\(\frac{6}{18}-\frac{6}{24}=\frac{1}{3}-\frac{1}{4}=\frac{4}{12}-\frac{3}{12}=\frac{1}{12}\)

D)\(\frac{5}{9}-\frac{3}{12}=\frac{5}{9}-\frac{1}{4}=\frac{20}{36}-\frac{9}{36}=\frac{11}{36}\)

Chúc bạn học tốt

=7/11+5/6+4/11-1/6

=(7/11+4/11)+(5/6-1/6)

=1+2/3

=5/3

\(A,\dfrac{7}{11}+\dfrac{5}{6}-\dfrac{-4}{11}-\dfrac{1}{6}\)

\(= (\dfrac{7}{11}+\dfrac{-4}{11})-(\dfrac{5}{6}-\dfrac{1}{6})\)

\(=\dfrac{3}{11}-\dfrac{2}{3}\)

\(= \dfrac{9}{33}-\dfrac{22}{33}\)

\(= \dfrac{-13}{33}\)

\(B,\dfrac{5}{9}.\dfrac{7}{3}+\dfrac{5}{9}.\dfrac{9}{13}-\dfrac{5}{9}:\dfrac{13}{5}\)

\(=(\dfrac{5}{9}.\dfrac{5}{9}:\dfrac{5}{9}).\dfrac{7}{3}+\dfrac{9}{13}-\dfrac{13}{5}\)

\(=(\dfrac{5}{9}.\dfrac{7}{3})+(\dfrac{9}{13}-\dfrac{13}{5})\)

\(=(\dfrac{5}{9}.\dfrac{21}{9})+(\dfrac{45}{65}-\dfrac{169}{65})\)

\(=\dfrac{35}{27}+\dfrac{-124}{65}\)

\(=\dfrac{2275}{1755}+\dfrac{-3348}{1755}\)

\(=\dfrac{-1073}{1755}\)