Đặt A = 4 + 6 + 8 + 10 + .... + 2012
SSH: (2012 - 4) : 2 + 1 = 1005
=> A = (2012 + 4) . 1005 : 2 = 1013040
\(\Rightarrow1013040.\frac{1}{1000}\left(\frac{1}{2}+\frac{3}{4}+\frac{5}{6}\right)=1013040.\frac{1}{1000}.\frac{25}{12}=1013040.\frac{1}{480}=\frac{4221}{2}\)