The Dozenal Society of America

The DSA is a voluntary, nonprofit education
corporation, organized for the conduct of
research and education of the public in the
use of dozenal (also called duodecimal or
base-twelve) in calculations, mathematics,
weights and measures, and other branches of
pure and applied science.

# Practice Your Dozenal Arithmetic

Test your dozenal arithmetic skills! Use "X" for ten
and "E" for eleven. Remember not to calculate in decimal
and convert the answer; calculate in dozenal to help you
memorize the dozenal arithmetic facts. They are much
easier and more regular in dozenal, so this should be a
help in doing so.

Addition |
Subtraction |
Multiplication |
Division