1616/1515 + 1616/3535 + 1616/6363 + 1616/9999
= 32/21 + 1616/6363 + 1616/9999
= 16/9 + 1616/9999
= 64/33
cách khác nhé:
\(\frac{1616}{1515}+\frac{1616}{3535}+\frac{1616}{6363}+\frac{1616}{9999}\)
\(=\frac{16}{15}+\frac{16}{35}+\frac{16}{63}+\frac{16}{99}\)
\(=16\left(\frac{1}{15}+\frac{1}{35}+\frac{1}{63}+\frac{1}{99}\right)\)
\(=16\left(\frac{1}{3.5}+\frac{1}{5.7}+\frac{1}{7.9}+\frac{1}{9.11}\right)\)
\(=8\left(\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right)\)
\(=8\left(\frac{1}{3}-\frac{1}{11}\right)\)
\(=\frac{64}{33}\)
