A percentage of a fraction is really small

$45\%$ of $\frac{6}{7}$ of $630$ is equal to $\frac {45}{100} \times \frac {6}{7} \times 630 = \frac {9}{20} \times \frac {6} { 7} \times 630 = \frac {9}{10} \times \frac {3}{7} \times 630 = 9 \times 3 \times 9 = 243$ .