3 nha chúc bạn học tốt k cho mình nha
thanks bạn
\(\frac{1}{2}+\frac{2}{4}+\frac{3}{6}+\frac{4}{8}+\frac{5}{10}+\frac{6}{12}\)
\(=\left(\frac{1}{2}+\frac{2}{4}\right)+\left(\frac{3}{6}+\frac{4}{8}\right)+\left(\frac{5}{10}+\frac{6}{12}\right)\)
\(=1+1+1\)
\(=3\)