Dr. Wright's Kitchen Table Math is what you're looking for. It explains fun ways of teaching basic numeracy to ages 2-8. It's what's recommended (and sold) by Art of Problem Solving for kids prior to Beast Academy.

http://www.amazon.com/Dr-Wrights-Kitchen-Table-Math/dp/0982921128
http://artofproblemsolving.com/store/item/ktm-1