Question

1/5•6+1/6•7+...+1/24•25

Answer 1

=1/5-1/6+1/6-1/7+....+1/24-1/25

=1/5-1/25

=5/25+(-1/25)

=4/25

tick nha

Answer 2

\(\dfrac{1}{5.6}+\dfrac{1}{6.7}+...+\dfrac{1}{24.25}\)

\(=\dfrac{1}{5}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{7}+...+\dfrac{1}{24}-\dfrac{1}{25}\)

\(=\dfrac{1}{5}-\dfrac{1}{25}\)

\(=\dfrac{4}{25}\)