RÚT GỌN
\(A=\frac{12+\frac{12}{7}-\frac{12}{25}-\frac{12}{71}}{4+\frac{4}{7}-\frac{4}{25}-\frac{4}{71}}:\)\(\frac{3+\frac{3}{13}+\frac{3}{15}+\frac{3}{15}+\frac{3}{101}}{5+\frac{5}{13}+\frac{5}{15}+\frac{5}{101}}\)
\(B=\frac{\frac{1}{51}+\frac{1}{52}+\frac{1}{53}+......+\frac{1}{100}}{\frac{1}{1.2}+\frac{1}{3.4}+\frac{1}{5.6}+.......+\frac{1}{99.100}}\)
cho 1 cai dung minh cho ban roi ma