Multiply the numbers in the numerator and the denominator.

$$\frac{1 \times 3}{3 \times 3} = \frac{3}{9}$$

The equivalent fraction is $\boxed{\frac{3}{9}}$.

$$\frac{3 \times 4}{4 \times 4} = \frac{12}{16}$$

The equivalent fraction is $\boxed{\frac{12}{16}}$.

$$\frac{3 \times 9}{10 \times 9} = \frac{27}{90}$$

The equivalent fraction is $\boxed{\frac{27}{90}}$.

$$\frac{14 \div 7}{21 \div 7} = \frac{2}{3}$$

The equivalent fraction is $\boxed{\frac{2}{3}}$.

$$\frac{3 \div 3}{6 \div 3} = \frac{1}{2}$$

The equivalent fraction is $\boxed{\frac{1}{2}}$.

$$\frac{6 \div 2}{10 \div 2} = \frac{3}{5}$$

The equivalent fraction is $\boxed{\frac{3}{5}}$.

$$\frac{16 \div 4}{20 \div 4} = \frac{4}{5}$$

The equivalent fraction is $\boxed{\frac{4}{5}}$.

$$\frac{20 \div 10}{30 \div 10} = \frac{2}{3}$$

The equivalent fraction is $\boxed{\frac{2}{3}}$.