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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+10)*5/3=6*(5)=30ǰӺ2

(1+2+3+4+5+...+n) ͨùʽΪ[n(n+1)]/2 Ϳ빹йʽ ⣺ ԭʽ =2(1+2+3+4+5+...+48+49+50) =2{[50(50+1)]/2} =5051 =2550

(2+4+6+...+100)-(1+3+5+...+99) =(2-1)+(4-3)+...+(100-99) =1+1+...+1 =50

8+2=4+6=7+1+2 8+2=4+6=7+2+1

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

Ŀԣ117172153 Ҳǵһλһλжֵһ лл

=1+3+5++99-2+4+6+8++100 =1+99{99-12+1}2-(2+100){(100-2)21}2 =50

4x-12=216

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