Synopsis
It is debatable whether babies around five months can "count", but it can be agreed there is an awareness of the concepts of increase or decrease.
Similar broadcast resources

Babies and proto-conversation | Baby Monthly
Two mothers do an experiment with their babies where they alternate being passive and involved, which showed the babies trying to use their expressions for further engagement.

Children and wordless thoughts | Teaching Today
It is thought that children in their early years can think wordlessly as they won't have grasped their native language.