My son speaks like a stereotypical native american in a bad 1950's western, while some other kids his age could be news anchors. But he can say his alphabet and recognize most letters. Why do I share this? To prove that toddlers of average intelligence can easily learn most tricks we put in front of them.
Kids are teachable. Ridiculously teachable. God made them that way, so mothers of average intelligence could teach them.
Part of my consternation with the Your-Child-Must-Do-Preschool mentality is that causes many mothers to doubt their ability to teach their child such basic things as colors, letters, numbers, or even theology. Just the other day, I overheard a mother explaining why they wanted to do private kindergarten: "I like that he would be learning about Moses and Noah."
What I would have said, if I didn't value social harmony, is "Your child can learn about Moses and Noah without going to private kindergarten. You have a Bible in the house, right?"
We teach our children how to build towers with their blocks, how to use utensils, eventually how to use a potty. Why do we doubt we can teach them other things as well? I mean, compared to potty training, I think numbers will be easy.