\(\frac{1}{2}\)+\(\frac{1}{6}\)+\(\frac{1}{12}\)+\(\frac{1}{20}+\frac{1}{30}\)=\(\left(\frac{6}{12}+\frac{2}{12}+\frac{1}{12}\right)\)+\(\left(\frac{30}{60}+\frac{20}{60}\right)\)
= \(\frac{9}{12}+\frac{50}{60}\)
=\(\frac{45}{60}+\frac{50}{60}\)
=\(\frac{95}{60}\)
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
= \(\frac{6}{12}+\frac{2}{12}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
= \(\frac{8}{12}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
= \(\frac{9}{12}+\frac{1}{20}+\frac{1}{30}\)
= \(\frac{4}{5}+\frac{1}{30}\)
= \(\frac{24}{30}+\frac{1}{30}\)
= \(\frac{25}{30}=\frac{5}{6}\)
Chúc bạn hok tốt !
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
\(=\frac{1}{1x2}+\frac{1}{2x3}+\frac{1}{3x4}+\frac{1}{4x5}+\frac{1}{5x6}\)
\(=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)
\(=1-\frac{1}{6}\)
\(=\frac{5}{6}\)
\(\frac{1}{2}+\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+\frac{1}{30}\)
\(=\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+\frac{1}{5.6}\)
\(=\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}\)
\(=\frac{1}{1}-\frac{1}{6}\)
\(=\frac{5}{6}\)
