Question

Tính 1/1.2 + 1/2.3 + 1/3.4 + 1/4.5 +1/5.6 

Answer 1

Tại sao ra kết quả như vậy hả bạn ???

Answer 2

=1/1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6

=1/1+-1/2+1/2+-1/3+1/3+-1/4+1/4+-1/5+1/5+-1/6

=1/1+-1/6=5/6

Answer 3

\(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\)

\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)

\(=1-\frac{1}{6}=\frac{5}{6}\)