Question

1/1*2+1/2*3+1/3*4+..........+1/999*1000+1

Answer 1

1/1*2+1/2*3+1/3*4+1/4*5+...+1/999*1000+1

=1-1/1000+1

=1000+1-1/1000+1

=1000/1001

Answer 2

1999/1000 

tớ gặp bài này rối, k nhé