INTRODUCTION
Many educational materials including
repeated simple arithmetic such as addition,
subtraction, and multiplication have been
used for effective math education. Kumon
Inc., one of the companies publishing such
material, claims that repeating simple
arithmetic activates wider area of both left
and right brain, whereas complex arithmetic
mostly activates the left hemisphere
(Kawashima, 2003). They measured the
brain activities of five college students using
functional magnetic resonance images
(fMRI). This was supported by Delazer
et al. (2003), who suggest that the left