There are 576 boys and 448 girls in a school that are to be divided into equal sections of either boys or girls alone. Find the total number of sections thus formed?

576 = 2 × 2 × 2 × 2 × 2 × 2 × 3 × 3
448 = 2 × 2 × 2 × 2 × 2 × 2 × 7
HCF = 2 × 2 × 2 × 2 × 2 × 2 = 64
Hence, number of classes required
$$\frac{{576}}{{64}} + \frac{{448}}{{64}}$$
= 9 + 7
= 16

Shortcut:
The numbers (3 × 3) and 7 are not a part of HCF. And sum of multiplication of these number is the required answer.