# Talk

## Maths - what on earth is partitioning and how come I can't do it?

(8 Posts)
saltire Fri 28-Sep-07 08:06:35

DS1 has brought homework home, maths which he hadn't done. It's maths and its called partitioning. I think he's doing it wrong, but he insists he isn't.

Heres one of the example
In my money box I ahve £29.65. I earn £12.76 pocket money. How much do I have altogether?

Now I worked it out the way I always do and came up with£42.41.
DS insists thats wrong and it needs to worked out like this

2 9 6 5
+ 1 2 7 6, and then add each number to the one under it, by partitioning, adding a line between them.

2+1,9+2,6+7,5+6.
he keeps coming up with 3131, but I don't know what he's doing with the spare 1's, in 9+2 for example, it's 11, but he's only putting down 1, and I don't know where the extra 1 goes,a dn he says that is how he has been shown how to do it.
I've confused myself , and I'm sure he is wrong because how can they teach children thats the way to do maths if the answer is wrong?

tiredemma Fri 28-Sep-07 08:09:41

DS1 had this at school the other day- he explained it to me ( But can I remember it to explain to you?? Nope.)

sorry. maths is not my strong point.

Hallgerda Fri 28-Sep-07 08:18:30

Yes, you're right. He's left out the awkward little bits that you and I call carrying figures. And yes, they are still used in the new-fangled method, which works something like:

<Partition both summands into powers of 10, you know, units, tens, hundreds, thousands>

2965 + 1276 = 2000 + 900 + 60 + 5 +1000 + 200 + 70 + 6

<Group units, tens, hundreds, thousands etc. together to add them>

= (2000 + 1000) + (900 + 200) + (60 + 70) + (5 + 6)

= 3000 + 1100 + 130 + 11

<Oh dear, you can add hundreds together and end up with thousands. Just have to partition again then...>

= 3000 + 1000 + 100 + 100 + 30 + 10 + 1

= 4000 + 200 + 40 + 1

= 4241

<At last!>

As you can see, it's really the method we know and love, just presented a bit differently.

saltire Fri 28-Sep-07 09:09:22

. And that's the method they teach them.......why?
It looks bloody difficult to me, but then I got thrown out of maths

Creole Fri 28-Sep-07 09:45:00

I'll do it like this:

29.65
12.76
.11 = 5+ 6 = 11
1.30 = 6+7 = 13
11.00 = 9+2 = 11
30.00 = 2+1= 3
42.41

You still carry the 1 over though, maybe I'm wrong!

saltire Fri 28-Sep-07 15:17:08

But I still don't see the point of doing it that way. Why not stick to the way it's always been done.

Hallgerda Sat 29-Sep-07 21:40:23

It's really equivalent to the method we know and love, and is supposedly easier to understand. Undoubtedly easier to cock up though

So, yes, I wish schools stuck to good old-fashioned column addition too. Just wait till you see what they do to multiplication and division...

Sat 29-Sep-07 21:45:49

oh gawd! I have all this to come!!!

Why do they change things....I have just had a problem with handwriting.

DS1 is 5 and trying to join his name up but he cant!!

I thought he could as he was trying to join an 'a' to an 'x'. In my day you could do this as the x was more 'curly(!)' than straight but that has been changed now and it is definitely an X.

that maths looks very complicated but it looks like Hallgerda has it sorted!

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