Gardner's theory argues that intelligence, particularly as it is traditionally defined, does not sufficiently encompass the wide variety of abilities humans display. In his conception, a child who masters multiplication easily is not necessarily more intelligent overall than a child who struggles to do so. The second child may be stronger in another kind of intelligence, and therefore may best learn the given material through a different approach (Learning Styles), may excel in a field outside of mathematics, or may even be looking through the multiplication learning process at a fundamentally deeper level that hides a potentially higher mathematical intelligence than in the one who memorizes the concept easily.
Some critics argue that many of Gardner's "intelligences" actually correlate with the g factor (General Intelligence), supporting the idea of single dominant type of intelligence. http://en.wikipedia.org/wiki/General_intelligence_factor