Students need to know all the vocabulary and symbols to really understand a mathematical situation. Students also need to be able to demonstrate what the situation is about. They can demonstrate by a drawings, hands-on activity, etc.
And the subject should be taught in a gradient step-by-step manner. If a student is having trouble at a particular step then it is necessary to go back to the previous step before proceeding. This is particularly important with the new common core rigorous program.
Common core Mathematics is not difficult to master if these steps are followed.
Teaching in this manner, a class or tutoring, I have had students really enjoy the challenge and obtain excellent results that they can apply in their life.
After all, the purpose in learning a concept is to be able to use it in life.