Vedic Mathematics is a system of math found in Vedas rediscovered in the early 20th century (or made up by some guy-- we're not about to go after the solution to that mystery while researching a DS non-game). It is based on sixteen sutras that provide simple methods for calculations.
Publisher Shinyusha's book Math Drills: The Indian Way is currently a massive hit in Japan and has sparked a Vedic math fad, not only among the school-aged, but among adults. And what is the other fad in Japanese education techniques? Right, the Nintendo DS. Shinyusha is partnered with GungHo in the development of Indian Style Calculation Drills. And now you know ... the rest of the story. Good day!