Even after receiving an education to an acceptable level of literacy, some people may continue to have great difficulty in understanding and manipulating numbers. In its extreme form, this revulsion against numbers has been termed number blindness. Acalculia, which is the inability to perform arithmetic operations, is seen most commonly with parietal lobe lesions.
Two aspects of innumeracy may be distinguished: the inability to think quantitatively and to realize the extent to which problems are problems of degree even when they appear as problems of kind; and the inability to make use of the scientific approach of observation, hypothesis, experiment and verification.
There have been few estimates of the extent of this problem, but it has been widely accepted that numbers do not mean much to most people although this is generally not the case where monetary questions are at issue. Otherwise well educated people fall victim all to often to the extreme misinterpretation of statistics which makes "pseudoscience" - phrenology, parapsychology, predictive dreams, astrology and television evangelism - so influential in daily life.
Students do not learn mathematics adequately because rote learning is emphasized at the expense of fundamental concepts and problem solving strategies.