This is an educational video from The Free Math Tutor which explains how and why should we expand fractions. This video is basically for kids who have just been introduced to fractions in mathematics.
The presenter explains using two examples, the above process. The first example is about adding two fractions with different numerators and denominators while the second example deals with listing a group of fractions in ascending order, again, the numerators and denominators are different.
Watch this video and learn how to expand the fractions and solve the examples.