Find gcd (57, 209). Hence or otherwise simplify the fraction $\frac{57}{209}$.
The factors of 57 are $\{1, 3, 19, 57\}$. The factors of 209 are $\{1, 11, 19, 209\}$. Therefore gcd(57, 209) is 19.
We can simplify the fraction by dividing the numerator and denominator by the gcd, as follows
$$\frac{57}{209} = \frac{57 \div 19}{209 \div 19} = \frac{3}{11}$$