\(\frac{12}{5}+\frac{23}{4}=\frac{48}{20}+\frac{115}{20}=\frac{163}{20}\)

\(=\frac{163}{20}\)

\(\frac{12}{5}+\frac{23}{4}\) 

\(=\frac{24}{20}+\frac{115}{20}\) 

\(=\frac{139}{20}\) 

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{3+6-2}{12}\)

\(=\frac{7}{12}\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{9}{12}-\frac{2}{12}\)

\(=\frac{7}{12}\)

\(\frac{3}{12}+\frac{2}{4}-\frac{2}{12}\)

\(=\frac{3}{12}+\frac{6}{12}-\frac{2}{12}\)

\(=\frac{7}{12}\)

\(12\frac{3}{7}\%+12\frac{5}{7}\%=\frac{176}{7}\%\)

2\(\frac{2}{12}\)+ X = \(\frac{5}{7}\)+ \(\frac{8}{12}\)

\(\frac{13}{6}\)+ X=\(\frac{29}{21}\)

X= \(\frac{29}{21}\)- \(\frac{13}{6}\)

X=\(\frac{-11}{14}\)

\(|2^2_{12}\)\(+x=\frac{5}{7}+\frac{8}{12}\)

\(2+x=\frac{5}{7}+\frac{1}{2}\)

\(2+x=\frac{17}{14}\)

\(x=\frac{17}{14}-2\)

\(x=\frac{-11}{14}\)

\(2\frac{2}{12}+x=\frac{5}{7}+\frac{8}{12}\)

\(\frac{26}{12}+x=\frac{29}{21}\)

               x  = \(\frac{29}{21}-\frac{26}{12}\)

              x  = \(\frac{-11}{14}\)

\(2\frac{4}{3}+\frac{4}{12}=\frac{2.3+4}{3}+\frac{4}{12}=\frac{10}{3}+\frac{4}{12}=\frac{40}{12}+\frac{4}{12}=\frac{44}{12}=\frac{11}{3}\)

\(2\frac{4}{3}=\frac{10}{3}\)

\(\frac{10}{3}+\frac{4}{12}=\frac{120}{36}+\frac{12}{36}\)

\(=\frac{132}{36}=\frac{22}{6}=\frac{11}{3}\)

\(-\frac{3}{4}=-\frac{15}{20}\)

\(\frac{4}{-5}=-\frac{16}{20}\)

Do \(-15>-16\)

\(\Rightarrow-\frac{3}{4}>\frac{4}{-5}\)

So sánh \(\frac{-3}{4}........\frac{4}{-5}\) hay \(\frac{-3}{4}.......\frac{-4}{5}\)

Ta có :

\(1+\frac{-3}{4}=\frac{1}{4}\)

\(1+\frac{-4}{5}=\frac{1}{5}\)

Vì \(\frac{1}{4}>\frac{1}{5}\Rightarrow1+\frac{-3}{4}>1+\frac{-4}{5}\Rightarrow\frac{-3}{4}>\frac{-4}{5}\)

\(\Rightarrow\frac{-3}{4}>\frac{4}{-5}\)

Vậy \(\frac{-3}{4}>\frac{4}{5}\)

13/4+23/6-4/2=39/12+46/12-24/12 

                    =85/12-24/12

                    =61/12

chúc bạn học giỏi

1/3+1/4+4/5-1/2=4/12+3/12+4/5-1/2=7/12+4/5-1/2=35/60+48/60-1/2=83/60-1/2=83/60-30/60

=53/60

MTC;60

20/60+15/60+12/60-30/60

=20+15+12-30

=17    nha bn

MẪU SỐ CHUNG NHỎ NHẤT LÀ 60

\(\frac{20}{60}+\frac{15}{60}+\frac{12}{60}-\frac{30}{60}=\frac{20+15+12-30}{60}=\frac{17}{60}\)