Question

Tính tổng sau: 1/1x2+1/2x3+1/3x4+........1/999x1000

Answer 1

=1 - 1/2 + 1/2 - 1/3 + ...... +1/999 - 1/1000

=1-1/1000

=999/1000

Answer 2

=1 - 1/2 + 1/2 - 1/3 + ...... +1/999 - 1/1000

=1-1/1000

=999/1000

Answer 3

=1-1/2+1/2-1/3+...+1/999-1/1000

=1-1/1000

=999/1000