"One is less than two."
You cannot say that. The word「ほど」should be followed by a negative one. We could use a phrase「ほど多くはない」to mean「より少ない」. The latter could be used in a mathematical manner; smaller than (and not equal to), as the example here. However, the former does not have such a precision;「日本の人口はアメリカほど多くはない。」"The population in Japan is not as large as that in the USA."