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ǰλãҳ>>1ʮ2ʮ3ʮ4ʮ5ʮʮ98ʮ99,ü㷽,(),...>>

1ʮ2ʮ3ʮ4ʮ5ʮʮ98ʮ99,ü㷽,(),...

1ʮ2ʮ3ʮ4ʮ5ʮʮ98ʮ99,ü㷽,(4950),(ӷ).:1ʮ2ʮ3ʮ4ʮ5ʮʮ98ʮ99=(1+99)+(2+98)+(45+55)+50=100*49+50=4900+50=4950 ļɾǴ,(1+99)(2+98)ҪǼ50 չ:ӷ:a+b+c=(a+b)+c=a+(b+c) ,Ȱǰ,ٺ͵, ȰѺ,ں͵һ,Ͳ,ӷ.ӷ:a+b=b+a ,λ,Ͳ,ӷ .

1-2+3-4+-99+100=50

199,298İ취

:1ʮ2ʮ3ʮ4ʮ99ʮ100=(1+100)+(2+99)+(3+98)++(50+51)=101+101+101++101 =101x50=5050

1+2+3+4++88+89=(1+89)*892=4005

1+2+3+4+5++100=5050 㷽Ϊ:۲֪,һȲе,dΪ1,Ϊ1,ĩΪ100,Ϊ100,ݵȲе͹ʽ(+ĩ)*/2ɵ (1+100)*100/2=5050.֪ʶչ:Ȳе͹ʽ,һȲеΪa1,ĩΪan,Ϊn,Ϊd,ôõȲ͹ʽΪ: ȱ,ȱָӵڶ,ÿһǰһıֵͬһһ,GPʾ.ȱеĹ,ͨĸqʾ(q0),ȱa1 0.{an}еÿһΪ0.ע:q=1 ʱ,anΪ.͹ʽΪ

1ʮ2ʮ3ʮ99=(1+100)X50-100=5050-100=4950

n(n+1)/2 5050 1+99=100,2+98=100,3+97=100.һ49һ,ټ50,ٰǸ100,Ҳ5050

1+100=101 2+99=101 3+98=10150101Ե5050

=1+99+3+97+5+95+49+51=2500

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