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Cave paintings in Indonesia have been discovered and recently researched. They clearly show a local variety of pig, identified by features of the body shape. The timescale has been reliably calculated by radioactivity decay measurements of the elements deposited over the markings.
The relevance of all the above paragraph lies in the observation that the illustrations of pigs clearly show four legs. The ice-age people observed, and replicated, the quantity of four. I doubt if they copied a life-model of a pig, in the darkness of the cave. So they must have remembered the 'fourness' of the legs. [Indonesian Ice-Age Cave Paintings]" title="Feature from the Smithsonian Magazine" target="_blank">[Indonesian Ice-Age Cave Paintings].
I do not wish to claim that these folk had the ability to count up to four, but it is an example of their mindfulness of something greater than one: in other words number.
This mental skill exemplifies the process taking place in the infant. Education theorists suggest that up to age three infants are not 'learning to count'. They are becoming aware of 'quantity' as a concept, and as they recognize the repeated nature of this experience their language develops a means of communicating it (influenced more-or-less by parents and kindergarten staff).
The reason this page has been written for the web is to demonstrate the importance of parental influence on their children from as soon after birth as they have time to put to it. Provide things to see, listen to, play with, experience: and provide them in quantity. And make time to encourage and enjoy their discovery. The investment will have marvellous returns.