I absolutely hate war, but WAR - the card game - has been tremendously helpful in teaching both of my children basic number skills. My 4year old is excellent at this game! Math for little kids has a little bit to do with numbers, and a lot to do with patterns, quantities, the concepts of less/more, and shapes.
WAR not only teaches number recognition but helps children quantify and compare the numbers (less/more.)
So do your kids a favor and play WAR with them. You'll be teaching them some pretty fun (and competitive) math. Who said math was boring? Definitely not me!