Bài 1 : Tính hợp lý :
a) A = 182 . \(\left(\frac{1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}}{2+\frac{2}{3}+\frac{2}{9}+\frac{2}{27}}:\frac{4-\frac{4}{7}+\frac{4}{49}-\frac{4}{343}}{1-\frac{1}{7}+\frac{1}{49}-\frac{1}{343}}\right)\) : \(\frac{919191}{808080}\)
b) C = \(-2+\frac{1}{-2+\frac{1}{-2+\frac{1}{-2+\frac{1}{3}}}}\)
c) D = \(\left(\frac{1}{1.2}+\frac{1}{3.4}+...+\frac{1}{2005.2006}\right)\): \(\left(\frac{1}{1004.2006}+\frac{1}{1005.2005}+...+\frac{1}{2006.1004}\right)\)