It's A Know Brainer

[Tokyo, May 20. Image via Getty]

TOKYO – MAY 20: Students from American schools in Japan practise abacus during the 27th annual abacus contest at the New Sanno Hotel on May 20, 2009 in Tokyo, Japan. American schools in Japan have brought in abacuses to develop the children’s calculating ability since 1981. (Photo by Junko Kimura/Getty Images)