Question

1/3*4+1/4*5+1/5*6+...+1/44*45

Tinh nhanh

Answer 1

\(\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}+...+\frac{1}{44.45}\)

\(=\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+...+\frac{1}{44}-\frac{1}{45}\)

\(=\frac{1}{3}-\frac{1}{45}\)

\(=\frac{14}{45}\)

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K cho mik với nhé Dang Thi Khanh Ly