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ǰλãҳ >> 2ʮ4ʮ6ʮ8ʮ1Oʮ12=()X()() >>

2ʮ4ʮ6ʮ8ʮ1Oʮ12=()X()()

㣠2ʮ4ʮ6ʮ8ʮ1Oʮ126X742 2ʮ4ʮ6ʮ8ʮ1Oʮ127X642

Ȳ 2+4+6+8+10.+96+98+100 =2+100x50/2/dzţ =102x50/2 =5100/2 =2550 ϣҵĻشаɣлл

(2+20)+ (4+18)+ (6+16)+ (8+14)+(10+12) = 22 * 5 = 110 ʵǵȲеͣʽ s=a1+n-1*d=a1+an*n/2

2+8=10 4+6=10 10+10+10=30 ʮ 65=30

1+9=10 2+8=10 ...ȵ 410+10+5=40+10+5=55

(2ʮ4ʮ6ʮʮ10o0)һ(lʮ3ʮ5ʮ7ʮ999)=2-1+4-3+6-5+...+1000-999=1+1+1+...+1=500

ùʽ βĺͳٳ2 1+17*17/2=153 ɣлл

5050

2ʮ4+6ʮʮ18+20 =2+205 =225 =110

2ʮ3һ4ʮ5ʮ6һ7ʮ8ʮ9һ1oʮǁʮ12һ13ʮʮ101ʮ102һ103 =(2+3-4)+(5+6-7)+(8+9-10)+.....(101+102-103) =1+4+7+11+....+100 =(1+100)*34/2 =1717 绹ף׷ʡ ϿҵĻش뼰ʱΪش𡿰ť ֻ...

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