1999/(1999+1999/2000)
=1999/[1999(1+1/2000)]
=1÷ (1+1/2000)
=1÷2001/2000
=2000/2001
如果帮到你,请记得采纳,O(∩_∩)O谢谢
=1999/[1999×(1+1/2000)]
=1/(2001/2000)
=2000/2001
1999/(1999+1999/2000)
同除1999得
1/(1+1/2000)
=2000/2001
=1999/[1999×(1+1/2000)]
=1/(2001/2000)
=2000/2001
小学5年级的奥数