A constructive definition of the continuum based on formal topology is give
n and its basic properties studied. A natural notion of Cauchy sequence is
introduced and Cauchy completeness is proved. Other results include element
ary proofs of the Baire and Canter theorems. From a classical standpoint, f
ormal reals are seen to be equivalent to the usual reals. Lastly, the relat
ion of real numbers as a formal space to other approaches to constructive r
eal numbers is determined.