Can number gestures solve the "gavagai" problem for children learning number words? In other words, does seeing a number gesture while hearing a number word focus children's attention on numeracy, as opposed to an infinite number of other possibilities? To find out, we conducted two studies: (1) a home-based study of 64 children, ages 14-30 months, observing natural interactions between parent and child; (2) a lab-based study of 112 children, ages 28-42 months, controlling for factors that varied freely in the observational study (e.g., the lab study was designed so that children could not "read" the correct answer off the experimenter's gesture). We found, in both home and lab studies, that adult number words with number gestures elicited child numeracy responses more often than adult number words alone. Interestingly, however, the child's number response was not always correct (particularly for large sets in the lab study). Children in both studies seemed to know that, when they saw a number gesture, a number response was called for--even if they did not know which number to respond with. Number gestures cue children into the fact that numeracy is the relevant dimension--akin to when a child knows a color response is needed but has no idea which color. Number gestures thus have the potential to focus attention on numeracy and ultimately foster number acquisition.