几道简便计算,速速回答!(1) (-1)+2+(-3)+4+.+(-99)+100(2) 3+(-6)+6+(-9)+9+.+27+(-30)(3) 1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2004+2005+(-2006)+(-2007)+2008.
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/18 05:11:09
![几道简便计算,速速回答!(1) (-1)+2+(-3)+4+.+(-99)+100(2) 3+(-6)+6+(-9)+9+.+27+(-30)(3) 1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2004+2005+(-2006)+(-2007)+2008.](/uploads/image/z/11516883-51-3.jpg?t=%E5%87%A0%E9%81%93%E7%AE%80%E4%BE%BF%E8%AE%A1%E7%AE%97%2C%E9%80%9F%E9%80%9F%E5%9B%9E%E7%AD%94%21%281%29+%28-1%29%2B2%2B%28-3%29%2B4%2B.%2B%28-99%29%2B100%282%29+3%2B%28-6%29%2B6%2B%28-9%29%2B9%2B.%2B27%2B%28-30%29%283%29+1%2B%28-2%29%2B%28-3%29%2B4%2B5%2B%28-6%29%2B%28-7%29%2B8%2B...%2B2004%2B2005%2B%28-2006%29%2B%28-2007%29%2B2008.)
几道简便计算,速速回答!(1) (-1)+2+(-3)+4+.+(-99)+100(2) 3+(-6)+6+(-9)+9+.+27+(-30)(3) 1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2004+2005+(-2006)+(-2007)+2008.
几道简便计算,速速回答!
(1) (-1)+2+(-3)+4+.+(-99)+100
(2) 3+(-6)+6+(-9)+9+.+27+(-30)
(3) 1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2004+2005+(-2006)+(-2007)+2008.
几道简便计算,速速回答!(1) (-1)+2+(-3)+4+.+(-99)+100(2) 3+(-6)+6+(-9)+9+.+27+(-30)(3) 1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2004+2005+(-2006)+(-2007)+2008.
(-1)+2+(-3)+4+.+(-99)+100
=[ (-1)+2]+[(3)+4]+.+[(-99)+100]
=(-1)+(-1)+(-1)+(-1).(-1)+(-1)
一共是100/2=50个(-1)
= (-1)×50
=-50
3+(-6)+6+(-9)+9+.+27+(-30)
=3+[(-6)+6]+[(-9)+9]+.[(-27)+27]+(-30)
=3+0+0+...+0+(-30)
=3-30
=-27
1+(-2)+(-3)+4+5+(-6)+(-7)+8+...+2004+2005+(-2006)+(-2007)+2008.
=[1+(-2)+(-3)+4]+[5+(-6)+(-7)+8]+...+[2005+(-2006)+(-2007)+2008].
=0+0+0+0+0.+0
=0