Question

1/1.2+1/2.3+1/3.4+......+1/999.1000

Answer 1

Ta có: \(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+.....+\frac{1}{999.1000}\)

\(=\left(\frac{1}{1}-\frac{1}{2}\right)+\left(\frac{1}{2}-\frac{1}{3}\right)+\left(\frac{1}{3}-\frac{1}{4}\right)+...+\left(\frac{1}{999}-\frac{1}{1000}\right)\)

\(=\frac{1}{1}-\frac{1}{1000}\)

\(=\frac{999}{1000}\)

Answer 2

1/1.2+1/2.3+1/3.4+...+1/999.1000

=1/1-1/2+1/2-1/3+1/3-1/4+...+1/999-1000

=1/1-1/1000

=999/1000

Answer 3

đề = 1 - 1/2 +1/2-1/3 + 1/3-1/4+.....+1/999-1/1000

     = 1-1/1000=999/1000

Answer 4

1/1.2+1/2.3+1/3.4+......+1/999.1000 = 499499/1998000

Answer 5

1/1.2+1/2.3+1/3.4+......+1/999.1000

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

=> 1-1/1000

=>1000/1000-1/1000

=> 999/1000