1) Tính:
\(A=\frac{2}{3.5}+\frac{2}{5.7}+\frac{2}{7.9}+........+\frac{2}{97.99}\)
\(B=\frac{\left(2^3.5.7\right).\left(5^2.7^3\right)}{\left(2.5.7^2\right)^2}\)
\(C=\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+.......\frac{1}{97.99}\)
\(D=\left(\frac{\frac{12}{1}-\frac{12}{5}-\frac{12}{487}}{\frac{4}{1}-\frac{4}{5}-\frac{4}{487}}\right):\left(\frac{\frac{5}{1}+\frac{5}{17}+\frac{5}{37}}{\frac{6}{1}+\frac{6}{17}+\frac{6}{37}}\right).\frac{505}{1818}\)
2) So sánh:
a)\(\frac{2008}{2009}+\frac{2009}{2010}\) và \(\frac{2008+2009}{2009+2010}\)
b) \(\frac{12}{23}\) và \(\frac{1212}{2323}\)
Giúp mình nha. Mai mình kiểm tra 45'.