Ta co: \(M=\frac{2013}{123456789}+\frac{2014}{987654321}=\frac{2013}{123456789}+\frac{2013}{987654321}+\frac{1}{987654321}\)
\(N=\frac{2013}{123456789}+\frac{1}{123456789}+\frac{2013}{987654321}\)
ma \(\frac{1}{987654321}< \frac{1}{123456789}\) nen \(M< N\)
\(M=\frac{2013}{123456789}+\frac{2014}{987654321}\)
\(N=\frac{2014}{123456789}+\frac{2013}{987654321}\)
\(M=\frac{2014}{987654321}-\frac{1}{987654321}\)
\(N=\frac{2014}{123456789}-\frac{1}{123456789}\)
Ta thấy \(\frac{1}{123456789}>\frac{1}{987654321}\)
\(\Rightarrow M< N\)