How children learn mathematics?
Interestingly children undertake every mathematics task is problem solving. It is the construction and connection of the existing ideas to the new ideas that link to the meaning of the potential relevant ideas when learning a new concept.
The existing ideas on their prior experience of knowledge with the combination of drill and practicing to reinforce in scaffolding new knowledge from prior knowledge further their conceptual understanding.
Children learn well when they are able to relate with concrete manipulative, pictorial visualise in their brain. Therefore it is concrete before pictorial and pictorial before abstract.