She said 2/8 is greater than 2/6 but that's wrong. 2/6 is greater than 2/8.
Pretend there are two people named Joe and Steve. Joe is 6 feet tall and Steve is 8 feet tall. They decide to jump into a mud pit that is 2 feet tall. Since Joe is 6 feet tall and the mud is 2 feet tall, 2/6 of Joe's body is covered in mud. Since Steve is 8 feet tall and the mud is 2 feet tall, 2/8 of Steve's body is covered in mud. This means that Joe will have more mud covering his body than Steve which makes 2/6 greater than 2/8.