The hypothesis that memory plays a central role in adult mental arithmetic is now universally accepted. It does mean, however, that a major upheaval in the mental arithmetic system occurs during preschool years. Children suddenly shift from an intuitive understanding of numerical quantities, supported by simple counting strategies, to a rote learning of arithmetic. It is hardly surprising if this major turn coincides with the first serious difficulties that children encounter in mathematics. All of a sudden, progressing in mathematics means storing a wealth of numerical knowledge in memory.
Most children get through as best as they can.
But as we will see, they often lose their intuitions about arithmetic in the process. Their intuitive math concepts beg to be developed. Instead, the practice is to subject them to senseless drilling. At that age the abstract reasoning is still lacking. Drilling does away with whatever vestiges of abstract math concepts children might have on an intuitive level.