At what age did you introduce math lessons to your children? I'm interested to see what age is appropriate for my daughter (she's two going on three) to begin lessons in math.

I know it's informal but I also know little by little I'm introducing Math to my 18 month-old daughter by teaching her how to count with her hands, count toy blocks and let her be familiarize with numbers using flash cards and those puzzle mats with numbers on it. But if you want to take it seriously (not that I'm not serious too haha), probably more in-depth in enhancing their skills on that, here's a good read for you: https://www.zerotothree.org/resources/299-help-your-child-develop-early-math-skills

Doesn't have to be formal! You can start at that age already - teach addition at the supermarket (how many things are going into the cart), subtraction at the dinner table (how many pieces of broccoli left after she eats one or two), fractions through pizza!