Early number competence is highly predictive of later mathematics achievement. The present study aims to examine how fundamental domain-general skills, including language, visual-spatial, and executive functions, together relate to early acquisition of numbers among very young children. A total of 109 Chinese children, aged approximately three years, in Hong Kong were tested individually on their number competence, receptive vocabulary, knowledge of written letters, rapid automatized naming, spatial perception, and behavioral executive skills. The results showed that vocabulary, letter knowledge, spatial perception, and executive skills all made a unique contribution to number competence. The findings add to the literature by documenting the critical importance of spatial perception and written language for early number learning. They also suggest that language, visual-spatial, and executive skills provide the building blocks for children's number acquisition at a very young age. (author abstract)