A key characteristic of human cognition, hypothesized to underlie the uniqueness of humans, is our ability to represent complex cognitive structures as a set of meaningful syntactic relations. In the domain of numbers, such syntactic representations are the key to the human ability to handle multi-digit numbers, however, we still have little understanding of the precise nature of the core syntactic representation of numbers. Here, I examined whether this core syntactic representation can be formed independently of semantic and lexical representations. Literate adults repeated sequences of number-like nonwords that had the morpho-syntactic structure of numbers but were otherwise unfamiliar and meaningless. Repetition accuracy was higher for grammatical sequences (“palir hundred tugumty-bab”) than for non-grammatical sequences made of the same words (“bab, tugumty, palir-hundred”). This effect, which mirrors similar findings with real numbers, indicates that when a sequence was grammatical, the participants represented its syntactic structure and used this representation to merge the nonwords into chunks in short-term memory, thereby improving memorization. Critically, because the stimuli were nonwords, I could conclude that the syntactic representation can exist even in the absence of semantic and lexical representations; and it can be created even without a number-word lexicon, merely on the basis of morpho-syntactic cues in the verbal stimulus. This fits the view of syntax as a set of separate cognitive processes, relatively independent of semantics.