Maths is more a matter of practice than theory as rightly pointed out by Santosh. I may add that Mathemeatics differs from narrative subjects like History and literature that can be taught in any sequence. Proper sequence is of paramount importance in Mathematics. Unless you know counting, you cannot learn addition and deduction. Multiplication and division follow. When a child is proficient in one step, only then he should be taught next step. Mathematics needs very clear understanding, practice and perfection whereas subjects like history and social sciences may be okay even with some vagueness and imperfection.
It is important for the parent try to understand where the child is going wrong and how the child got there, so that the we can correct misconceptions.....