A number whose decimal representation eventually becomes periodic (i.e., the same sequence of digits repeats indefinitely) is called a repeating decimal. Numbers such as 0.5 can be regarded as repeating decimals since . All Rational Numbers have repeating decimals, e.g., . However, Transcendental Numbers, such as do not.

**References**

Ball, W. W. R. and Coxeter, H. S. M. *Mathematical Recreations and Essays, 13th ed.* New York: Dover, pp. 53-54, 1987.

Courant, R. and Robbins, H. ``Rational Numbers and Periodic Decimals.'' §2.2.4 in
*What is Mathematics?: An Elementary Approach to Ideas and Methods, 2nd ed.*
Oxford, England: Oxford University Press, pp. 66-68, 1996.

© 1996-9

1999-05-25