ta có: 1-31/61=30/61 và 1-311/611=300/611
vì 30/61<300/611 nên 31/61<311/611
\(\frac{31}{61}=1-\frac{300}{610}\)
\(\frac{311}{611}=1-\frac{300}{611}\)
Vì \(\frac{310}{610}>\frac{300}{611}\)
\(\Rightarrow1-\frac{300}{610}< 1-\frac{300}{611}\)
Vậy\(\frac{31}{61}< \frac{311}{611}\)