Tính A=\(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+..........+\frac{1}{2017\cdot2018}\)
B=\(\frac{1}{1\cdot3}+\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+..........+\frac{1}{2015\cdot2017}\)
C=\(\frac{1}{1\cdot4}+\frac{1}{4\cdot7}+\frac{1}{7\cdot10}+..........+\frac{1}{2017\cdot2020}\)
Ai làm nhanh nhất mình sẽ Tick cho nha.