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1ʮ2ʮ3ʮ4ʮ5ʮ6ʮ7дɳ˷ʽ

47=28

1+2+3+4.......+50 =(1+50)502 =51502 =25502 =1...

1ʮ2ʮ3ʮ4ʮ5ʮ6ʮ7......ʮ49ʮ50 =(1ʮ50)*50/2 =51*50/2 ...

¥ѧʦ̵ģ1+9 2+8ܹĸʮԭһ10 мõ5*10+5

=(1+10)+2+9+3+8+4+7+5+6=511=55

1ʮ2ʮ3ʮ4ʮ5ʮ6ʮ7ʮ8ʮ9 =1+9+2+8+3+7+4+6+5 =1...

ùʽ βĺͳٳ2 1+17*17/2=153 ɣлл

ͷβӶ104Σ ټм5. Ϊ4*10+5=45.

ѽ 5+3=8 6+2=8 7+1=8 4+4=8 ЩӶ8

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

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