Compositional capacity (i.e., chunking four objects as two sets of two) can extend 12- to 14-month-old infants’ working memory capacity from three to four1,2,3. Here we ask whether numerical composition supports 3- to 4.5-year-olds’ creating representations of large exact numbers such as five. In a non-verbal object-tracking task (See Fig1a), subset-knowers and most young CP-knowers failed to track exactly five objects. In two experimental manipulations, we provided children with spatiotemporal, linguistic, and/or color chunking cues. If tracking sets of five as a composition of two and three is within children’s compositional capacities, they should perform better than children from baseline. We found no evidence that 3- to 4.5-year-olds can represent exactly five by composing representations of two and three (Exp.1: F(4, 133) = 5.69, β = -0.03, p = .509; Exp.2: F(4, 143) = 4.94, β = -0.03, p = .587).