New evidence from Flanders and the Netherlands demonstrates that age heaping was gradually diminishing in large parts of the Low Countries during the sixteenth century, that (unexpectedly) almost no gender gap was apparent in the change (women even outperforming men at times), and that differences between town and countryside were small. These findings suggest an early rise in numeracy (or at least a “number sense”) in both urban and rural areas, linked to demographic change and commercial development. Between 1600 and 1800, Flanders, in particular, seems to have lost its strong distinctiveness in this regard.