Question

tính 1/2*3+1/3*4+1/4*5........+1/9*10 giúp mình nhé

Answer 1

1/1*2+1/2*3+1/34+1/4*5+1/5*6

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

=1-1/6

=5/6

Answer 2

 1/2*3+1/3*4+1/4*5........+1/9*10 mà bạn

Answer 3

\(=\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{9}-\dfrac{1}{10}\\ =\dfrac{1}{2}-\dfrac{1}{10}=\dfrac{4}{10}=\dfrac{2}{5}\)