Tính

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Bài 3: Tính

a) \(\frac{2}{9.5} + \frac{8}{5.7} + \frac{2}{7.9} + \frac{2}{6.3.65}\)

b) \(\frac{1}{1.3} + \frac{1}{5.5} + \frac{1}{5.7} + \frac{1}{19.21}\)

c) \(\frac{2}{3} + \frac{2}{6} + \frac{2}{10} + \frac{2}{15} + \frac{2}{45}\)