Real Money, Real Math

Spring cleaning unearthed a dress my mother made for me when I was seven and a bin of of forgotten pennies.

Me: You can have 'em but you'll need to count them out to see how many there are.
Kid, now wearing the dress (it fits!): How should I count them? 
Me: How about by twos?

At 100:
Kid: I need a helper!
Me: Oh, I'm too busy making dinner.  You can do it.

At the second 200:

Kid: I need an assistant!

Me: Nope, sorry.  I'm still making dinner.  Papa is busy vacuuming.

Kid: This is tiresome....Go look for a two dollar bill.

Me: Count them all and then I'll get out the paper money.

Kid: Do you know a quicker way?  By threes?

Me: How about by fives?

Kid: Okay...[counts 100 pennies out by fives]...Can I have a three dollar bill now?

At 400:
Kid: How about a four dollar bill? 
Me: Are you kidding?  There's no such thing, you goof!

Kid: I really, really want this to go faster....I know, you count out the pennies into tens and I'll count them up from there."
Me: (Nice try, kid.) Dinner's almost ready...

Done!  $4.73.  She made it an even five dollars with change from her wallet.

"I have enough to go buy ice cream!"  Well...
"It's my money, I can decide what I want to do with it!"  Well...

"I know...lipstick!"

I know it seems like this was all about the counting, but from my vantage point it was really more about strategy and predictions.  How much money am I going to end up with?  What is the quickest way to count it all up?  Can I get someone to help me?  How much do I have all together?  How much can five dollars buy? 

Real money means real life economics.  Real money means developing strategies and making real choices.  How much do I have?  Do I really need/want one more $1.00 stuffed kitty from Goodwill, or that china figurine, or do I want to wait and save my money for something else?  How much more will I need to earn/save before I can buy x, y or z?   Interacting with the realities of real money is another great example of real power.