Tính:
a) A= 2100 - 299 - 298 -....- 2
b) B= (1-\(\dfrac{1}{2}\)) . (1-\(\dfrac{1}{3}\)) . (1-\(\dfrac{1}{4}\) ) .........(1-\(\dfrac{1}{2018}\))
c) C= (1+\(\dfrac{1}{2}\)) + (1+\(\dfrac{1}{3}\)) + (1+\(\dfrac{1}{4}\)) +.....+ (1+\(\dfrac{1}{2018}\))
d) \(\dfrac{1}{1.2}\) + \(\dfrac{1}{2.3}\) + \(\dfrac{1}{3.4}\) +...+ \(\dfrac{1}{99.100}\)
e) \(\dfrac{1}{3.5}\) + \(\dfrac{1}{5.7}\) + \(\dfrac{1}{7.9}\) +....+ \(\dfrac{1}{97.99}\)
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