lists and gifts

The kids have made their Christmas wish lists, but what they don't know is that I have a mathematical formula that determines the probability of them receiving the asked for gift.
it goes like this

$= cost of desired object
t= time they will spend enjoying/using the object
s= storage space the thing will take up
n= number of parts involved

the formula looks like this:

$ x t/s x n

so for example Legos would be cost: moderate (depending on the set) times the time they will play with it (high), divided by the storage space (low) times the number of pieces (high)

Legos area possibility.

To not give anything away, I will just call this next thing an American Whirl Ball

cost= high
time playing with it = low
Storage space = high
Number of pieces = low

I don't think it's going to happen.

One thing I have noticed is that Christmas is a month long classroom with so much to teach us about ourselves, our relationships, our wants and our needs. As I read the kids lists I understood , just a little better about God and his relationship to us as our parent. We can ask for whatever we want, but like our children, we might not understand which things have the most value. As a parent, I can read the list and know how much they are going to enjoy each thing they ask for. Is it worth the cost? Is it something they really want or did they just put it on the list because the commercial looked so cool.

Matthew 6:11
If ye then being Evil, know how to give good gifts unto your children, how much more shall your Father which is in heaven give good things to them that ask him?