Question

1/3*4 + 1/4*5+ 1/5*6+...+ 1/9*10 + 1/10*11

Answer 1

\(\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}+...+\frac{1}{9\times10}+\frac{1}{10\times11}\)

\(=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{9}-\frac{1}{10}+\frac{1}{10}-\frac{1}{11}\)

( gạch bỏ các phân số giống nhau )

\(=\frac{1}{3}-\frac{1}{11}\)

\(=\frac{8}{33}\)

CHÚC BN HỌC TỐT!!!

Answer 2

cảm ơn