Tính :
A = \(\dfrac{2}{60.63}+\dfrac{2}{63.66}+..........+\dfrac{2}{107.120}+\dfrac{2}{2006}\).
B = \(\dfrac{5}{40.44}+\dfrac{5}{44.48}+.....+\dfrac{5}{76.80}+\dfrac{5}{2006}\).
C = \(\dfrac{1}{10}+\dfrac{1}{40}+\dfrac{1}{88}+\dfrac{1}{154}+\dfrac{1}{238}+\dfrac{1}{340}\).
D = \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}+.........+\dfrac{1}{2015.2018}\)