the New "new math"

My grandma used the term "new math".  And she was a school teacher.  She is long since passed, she was born in 1901 to give you an idea of her era.

Ryan has been struggling with subtracting large numbers.  I've been showing him how to borrow, but he's lazy and just wants to subtract the small number from the large number regardless of whether it's proper. 

Or so I assumed he was being lazy. 

Until I was checking Jake's math homework today.

Freaky stuff they are learning, I tell ya.

Here's the equation: 851 - 569   (I wish I could type this out like I can write it on paper)

You start with the numbers on the left.  If the top number is larger than the bottom number, you put a plus sign.  And then you write down the difference of the 100's.  So you would write +300  (which is 800 - 500)

If the top number is smaller than the bottom number, you put a - sign.  And then write down the difference of the 10's.  So you would next write -10  (which is 50 - 60).

So in the ones spot, you would write -8  (which is 1-9). 

So far you have, 851 - 569 = +300 - 10 - 8

When you calculate 300 - 10 - 8  you get 282 which is the correct answer! 

What?????  How did that happen????  I've not figured out the mathematical logic to this yet.

And that's not all.  They are using the Everyday Mathmatics curriculum.  Which teaches like 12 different methods to add, and then 12 different methods to subtract, you get the idea.  I just glanced at Jake's math workbook check out what they've been learning lately: "trade first subtraction" (which I think is OUR way), "partial differences subtraction" (the method I just illustrated),  and "subtraction by counting up" (I glanced at that, and realized that that's what I do in my head a LOT).

A lot of moms HATE Everyday Mathmatics.  The jury's still out for me.  Because I understand that a lot of people don't process math easily in the way that we were taught.  And this method is supposed to help the child learn math by presenting a number of methods so they can pick the one that works for them.  I'm all for that.  As long as they don't get confused in the meanwhile. 

A con to E.M. is that you have to do it throughout your schooling.  So the new kids that move here are having a tough time of it.  I'm sure they'll get it soon enough, because E.M. is nothing if not repetitive.  It's learn a little, move on, learn a little, move on, etc. then rotate back and start all over again.  Feeds it to them in little pieces and repeats.

I think we have Ryan straightened out now.  He saw me showing that method to Gary, and his eyes lit up.  He said he likes that method.  It was easy to him.  So good, a connection was made.  THere's hope.