I'm having fun teaching my 4-year-old math. After counting, addition was easy by holding up fingers or drawing dots. Then, subtraction came by counting backwards or crossing out dots.
A couple of weeks ago we started multiplying. To do 5 * 3, we make 5 circles, draw three X's in each circle, and then count them up.
Last week, we started dividing. To do 16 / 3, he'll draw 16 X's, then circle 3, then 3 more, etc. At the end there is one left over (poor little guy). Then, he counts up the circles and writes: 5 R 1.
We go up and down the stairs for positive and negative numbers. He really enjoys all this. Kids enjoy almost anything you do together. He'll even sit down and write his own problems, and problems for me to do.
I'm not expecting too much from the schools on math when he starts in a couple years, so I'm hoping to cultivate that interest at home, and maybe he can share it with his classmates.
Make sure you teach the "tricks". Those are amusing. I'm sure you can find a bunch online.
For example, a trick to multiplying by 9: hold up all 10 fingers, and then put down the one that matches what you are multiplying. The answer is the number of fingers still up (appending the count of those to the left of the down finger to the count of those to the right).
Example in ASCII Art: 9 x 4:
! ! ! . ! ! ! ! ! !
left hand right hand
4th finger is down. 3 up on the left side, 6 up on the right. 9 x 4 = 36.
I like the X9 trick. I'm surprised how many of my adult friends have never seen it.
The "tricks" he likes right now are the ones he can understand like n * 1 = n for any value of n or n / 1 = n (because you have one circle around everything).
I've tried showing him some tricks, but they aren't surprising and cool to him yet.
A couple of weeks ago we started multiplying. To do 5 * 3, we make 5 circles, draw three X's in each circle, and then count them up.
Last week, we started dividing. To do 16 / 3, he'll draw 16 X's, then circle 3, then 3 more, etc. At the end there is one left over (poor little guy). Then, he counts up the circles and writes: 5 R 1.
We go up and down the stairs for positive and negative numbers. He really enjoys all this. Kids enjoy almost anything you do together. He'll even sit down and write his own problems, and problems for me to do.
I'm not expecting too much from the schools on math when he starts in a couple years, so I'm hoping to cultivate that interest at home, and maybe he can share it with his classmates.