This is a simple exploration of ten. You can do it with all the numbers, but here a five year old is getting some basic information about 10. Ten is two fives, we have already built tens out of nine and one, eight and two etc...so we "know" a ten can be made of two fives, now we can see it can also be made out of five twos....

Just to make sure we put the fives on the twos and see they are exactly the same...

Then we lined them up and counted and compared.

We can do this with twelves and fifteens etc...

This is counting that sets up for multiplication...note we aren't even using symbols yet, just the blocks.