Bài 1: Thực hiện phép tính 1 cách hợp lý :
\(a\)) \(\left(1+\frac{1}{1.3}\right).\left(1+\frac{1}{2.4}\right).\left(1+\frac{1}{3.5}\right)...\left(1+\frac{1}{2009.2011}\right)\)
\(b\)) \(\frac{16}{9}-\frac{1}{36}-\frac{1}{28}-\frac{1}{21}-\frac{1}{15}-\frac{1}{10}-\frac{1}{6}-\frac{1}{3}-1\)
\(c\)) \(\frac{0,4-\frac{2}{9}+\frac{2}{11}-\frac{2}{37}}{1,4-\frac{7}{9}-\frac{7}{11}-\frac{7}{37}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,785+0,7}\)