Just "taught" my DD(4) to add and subtract 2 and 3 digit numbers (no carrying numbers yet). I showed her one simple math problem and she kept asking for more and more and more...and then said "let's review our work" lol

In addition, she is still in the process of figuring out / memorizing basic math facts and used the following process to figure out a what 3+ 4 equals..."I know 3+3 = 6, so 1 more must be 7" I think I may have shown her that once or twice...but it has been awhile and she just pulled it out of her memory to use it...
Hard to think that she has 1 more year until kindergarten...