(1)=1-(1/3)+(1/3)-(1/5)+……+(1/97)-(1/99)
=1-(1/99)
=98/99
(2)=(1+3+5+7+9+11)+〔(1/2)-(1/5)+(1/5)-(1/7)+……+(1/17)- (1/20)〕
=36+〔(1/2)-(1/20)〕
=36+(9/20)
=36(9/20)
括号只是让分数不和整数弄混.
(1)=1-(1/3)+(1/3)-(1/5)+……+(1/97)-(1/99)
=1-(1/99)
=98/99
(2)=(1+3+5+7+9+11)+〔(1/2)-(1/5)+(1/5)-(1/7)+……+(1/17)- (1/20)〕
=36+〔(1/2)-(1/20)〕
=36+(9/20)
=36(9/20)
括号只是让分数不和整数弄混.