Tính tổng:
a) \(\frac{1}{2.4}\)+ \(\frac{1}{4.6}\) + \(\frac{1}{6.8}\) + ....... + \(\frac{1}{98.100}\)
b) \(\frac{1}{1.5}\) + \(\frac{1}{5.9}\) + \(\frac{1}{9.13}\) + ........ + \(\frac{1}{201.205}\)
c) \(\frac{6}{3.5}\) + \(\frac{6}{5.7}\)+ \(\frac{6}{7.9}\) + .......... + \(\frac{6}{97.99}\)
d) \(\frac{4}{8.11}\) + \(\frac{4}{11.14}\) + \(\frac{4}{14.17}\)+ ........ + \(\frac{4}{98.101}\)