Question

1 phần 1.2 + 1 phần 2.3 + 1phần 3.4+ .....+1 phần 99.100

Answer 1

giúp vs

Answer 2

= 1- 1/2 + 1/2 - 1/3 + 1/3 - 1/4 +... + 1/99 - 1/100

= 1 - 99/100

= 1/100.

Answer 3

\(\dfrac{1}{1.2}+\dfrac{1}{2.3}+\dfrac{1}{3.4}+...+\dfrac{1}{99.100}\)

=\(\dfrac{1}{1}-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

=\(\dfrac{1}{1}-\dfrac{1}{100}=\dfrac{100}{100}-\dfrac{1}{100}\)

=\(\dfrac{99}{100}\)