Please teach me what is "learning gap"

Basically, the learning gap is the difference between what your child HAS ALREADY learned in comparison to what they ARE EXPECTED TO LEARN AND UNDERSTAND. So for example, there could be a learning gap for a 5th grader who hasn't yet learned multiplication or division. The gap comes from the fact that most 5th graders are already learning/have learned that topic. It's usually based on individual performance, though.