102+104+106+108+.+206的和寻找规律计算102+104+106+```````````+2002的值

问题描述:

102+104+106+108+.+206的和
寻找规律计算102+104+106+```````````+2002的值

原式=(102+206)*(206-102+1)/2
=16170
原式=(102+2002)*(2002-102+1)/2
=1999852

(2002+102)*[(2002-102)/2+1]/2=1000452

=(102+2002)*[(2002-102)/2+1]/2
=2104*951/2
=1000452

等差数列嘛
用等差数列前n项和公式
Sn=na1+n(n-1)d/2
a1=102
d=2
n=(2002-102)/2+1=951
sn=951*102+951*950=1000452