Most parents who have infants in child care are hoping that they will be loved and nurtured, held and rocked, sung to and responded to. I would imagine that parents of children this age are not really thinking about math yet even thought they are definitely thinking about language.
I have frequently written about consistency as the foundation of mathematical concepts in infancy. How can we explain this to parents so it makes sense to them? Sometimes it is best to model behaviors for others so they intuit what we are doing and adopt the behaviors themselves.
Therefore, when an infant is dropped off in the morning, greet the child the same way each and every day. This consistency will be communicated to the parents, simply by doing it. Ask the parents the same series of questions each morning, in the same order, if possible, to model the same thing.
As time passes this subject would be a great idea for a newsletter. You could explain the ideas that infants learn about sequencing through the sequential patterns of the events of their days. This helps support something that we as ECE professionals have known forever; that consistent care matters.