-Ta có \(\frac{19}{18}=1+\frac{1}{18}\)
\(\frac{18}{17}=1+\frac{1}{17}\)
Vì \(\frac{1}{18}< \frac{1}{17}\)(=) \(1+\frac{1}{18}< 1+\frac{1}{17}\)(=) \(\frac{19}{18}< \frac{18}{17}\)
ta có \(\frac{19}{18}-1=\frac{1}{18},\frac{18}{17}-1=\frac{1}{17}.\)
\(\frac{1}{18}< \frac{1}{17}\)
=>\(\frac{19}{18}< \frac{18}{17}\)
xong r đó
Ta có :
\(\frac{19}{18}=\frac{19}{18}-1=\frac{19}{18}-\frac{18}{18}=\frac{1}{18}\)
\(\frac{18}{17}=\frac{18}{17}-1=\frac{18}{17}-\frac{17}{17}=\frac{1}{17}\)
Mà : \(\frac{1}{18}< \frac{1}{17}\)
\(\Rightarrow\frac{19}{18}< \frac{18}{17}\)