Question

Tính tổng 1/5.6+1/6.7+1/7.8+...+1/24.25

Answer 1

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

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

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

Answer 2

\(=\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+...+\frac{1}{24}-\frac{1}{25}=\frac{1}{5}-\frac{1}{25}=\frac{4}{25}\)

Answer 3

1/5.6+1/6.7+1/7.8+...+1/24.25

= 1/5-1/6+1/6+1/7-1/8+...+1/24-1/25

= 1/5-1/25

= 5/25-1/25

= 4/25

k mik nhé mọi người