Quick way to get started: find numbers and letters in anything they are interested in. Kids love helping their parents and cooking with them using recipes and measuring stuff uses letters and numbers.
Thanks! We do do this like counting cars or clothes. He is good at counting from 1-20 so I think we are going to move to the concept of adding/subtractions. Probably going to use fruits.
I personally think focusing on discrete math is a mistake, though everybody does it. Kids know the world is continuous* — just consider Piagetian experimentation in the bath — so opportunities to think that way are just as important, and I suspect more intuitive. The downside is my kid wanted to major in pure math.