5/6-7/12+9/20-11/30+...-99/2450=?
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5/6-7/12+9/20-11/30+...-99/2450=?
![5/6-7/12+9/20-11/30+...-99/2450=?](/uploads/image/z/19594861-61-1.jpg?t=5%2F6-7%2F12%2B9%2F20-11%2F30%2B...-99%2F2450%3D%3F)
5/6-7/12+9/20-11/30+...-99/2450
=(1/2+1/3)-(1/3+1/4)+(1/4+1/5)-(1/5+1/6)+...-(1/49+1/50)
=1/2-1/50
=24/50
=12/25
再问: 那(1/2+1/3)-(1/3+1/4)+(1/4+1/5)中的+1/4)+(1/4就不能抵消啊
再答: =1/2+1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7+....
=(1/2+1/3)-(1/3+1/4)+(1/4+1/5)-(1/5+1/6)+...-(1/49+1/50)
=1/2-1/50
=24/50
=12/25
再问: 那(1/2+1/3)-(1/3+1/4)+(1/4+1/5)中的+1/4)+(1/4就不能抵消啊
再答: =1/2+1/3-1/3-1/4+1/4+1/5-1/5-1/6+1/6+1/7+....
5/6-7/12+9/20-11/30+13/42
1+1/2-5/6+7/12-9/20+11/30-13/42+15/56=?
找出规律,1-5/6+7/12-9/20+11/30-13/42=
1又2/1-6/5+12/7-20/9+30/11-42/13=?
1/2-5/6+7/12-9/20+11/30-13/42+15/56=
6/5-12/7+20/9+-30/11+42/13=?要用简便算法.
1-3/2+5/6-7/12+9/20-11/30+.-19/90+21/110=?
5/6-7/12+9/20-11/30+……-19/90+21/110 =
30分之11-20分之9+12分之7-6分之5+2分之1=
3/5+6/7+5/6+7/12+9/20+11/30+13/42=小学奥数,
5/6-7/12+9/20-11/30+……+18+19/18*19-19+20/19*20=?
3/2-5/6+7/12-9/20+11/30-13/42 = = = 简便算