Spatial-numerical associations were initially studied using chronometric methods to reveal the orientation of the mental number line (SNARC effect; Dehaene, Bossini, and Giraux, 1993). Recent evidence has shown that unconstrained spatial movements can be valuable in the study of embodied number representations (Fischer and Campens, 2009). We used the Xbox Kinect to record arm movements in a parity judgment task. We replicated SNARC in the horizontal dimension and found a similar trend in the vertical dimension. Movement amplitudes were also affected by number magnitude. Together, these results generalize evidence for the mental number line to everyday behaviors and suggest that natural user interfaces (NUI) can be used to study embodied cognition.