1+2+······+2007+2008=（ ）从1一直加到2008,求简算过程.要写完整过程

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1+2+······+2007+2008=（ ）从1一直加到2008,求简算过程.要写完整过程
1+2+······+2007+2008=（ ）
从1一直加到2008,求简算过程.
要写完整过程

1+2+······+2007+2008=（ ）从1一直加到2008,求简算过程.要写完整过程
这是一个等差数列,和=（首相+尾项）*项数/2=(1+2008)*2008/2=2017036
如果你不知道公式,也没关系.令2008+2007+……+2+1=x,把这个和你的式子相加,是不是很明了了

1+2+······+2007+2008
=(1+2008)*2008/2
=2017036

1 + 2 +......+ 2007 + 2008
2008+ 2007 +......+ 2 + 1
上下两个式子相加就是2*（1 + 2 +......+ 2007 + 2008） 又因为1+2008=2009,2+2007=20...

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1 + 2 +......+ 2007 + 2008
2008+ 2007 +......+ 2 + 1
上下两个式子相加就是2*（1 + 2 +......+ 2007 + 2008） 又因为1+2008=2009,2+2007=2009，.....，2008+1=2009, 总共有2008个2009，即2*（1 + 2 +......+ 2007 + 2008）=2008*2009
所以1 + 2 +......+ 2007 + 2008=2008*2009/2

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