Chunking in year 5!

Discussion in 'Primary' started by andyknox1, May 16, 2011.

1. andyknox1

Why do the children struggle so much with it? Any secrets for success or variations?

Thanks

andyknox1@hotmail.com

2. Lightbulb100

What specifically do yours struggle with? My main probs have always come with them having poor multiplciation knowledge therefore picking rubbish numbers to chunk by. E.g. if it was 501/7, loads of mine would initally keep chunking in groups of 10, instead of recognising that they could do 70 lots based upon their prior knowledge that 7x7 is 49 so 7x70 is 490.
So...we did loads of work based on using what you already know to answer questions with regards to multiplication and division.
Subtraction often lets them down as well, so we did quite a bit of revision on this as well. We also held numeracy workshops for parents to show them the strategies used in school.

3. lindaayers

We have also found chunking to be problematic, mainly that it's really only the more confident that get it, because they know their tables and how many to chunk. At a recent Maths inset we were advised to try using a number line instead. I tried this last week with my year 5s and it worked much better. Instead of subtracting the chunks, draw a number line and jump along it in jumps of however many, until you get to the number you're dividing into. So if it's 324 divided by 3, jump along the number line 100 lots of 3 to get to 300. Then jump along another 8 lots of 3 to get to 24, add the 100 and the 8 together and there's your answer. It means the children don't need to be doing subtracting, just counting along the number line. Loads better.

4. lucylollipopOccasional commenter

So if so many children struggle with chunking, why are we not allowed to teach them the much easier standard short division method? Most of my class found it much easier, but I was instructed to stop teaching that method and do chunking instead.

5. WolfPaulOccasional commenter

Good question. I suspect that you have been so instructed simply because chunking is currently in vogue.
We ditched chunking a couple of years ago, much to the relief of children, staff and parents. Nearly all children can now divide accurately.

6. must be crazy!

I must be honest, I teach the lower set in year 4 and have covered all the operations EXCEPT

7. must be crazy!

I teach the lower set in year 4 and have covered all the operations EXCEPT division and especially chunking! It is my first year in KS2, and I dont feel confident enough in it myself, to be able to teach it properly! I know I must, but I will admit to putting it off for as long as possible ...

8. missblack86

The BIG problem with the short division method is that is actually doesnt teach the process/method with any depth of understanding. The other, more significant problem is that it doesn't always work leaving the children at a dead end. e.g. 189/19 - no cheats way round this one!
I teach chunking using the standard method and also use the numberline method too - chn tend to prefer one or the other, but admittedly do show them the short division method too. I teach Y6 and really believe that the best scenario is that children know and understand more than one way or method of doing things - in reality this isnt the case. But the children do need to have a strategy they can rely on - chunking im afraid is the most reliable method despite the fact that it does depend on the chn having decent knowledge of x tables.
In Y4/5 if you start with simple numbers e.g. 96/8 and really focus on the method rather than the answer, when you move onto larger amounts the children will already feel confident with the method and things should (hopefully) fall into place.

9. missblack86

Im interested to know what method you have introduced to replace it WolfPaul?

We start with division on a number line too, then show how this translates into chunking, if the children have a firm grasp on the former ( and of their times tables) then they generally "get" the latter. It is when children don't really understand division on a number line that they can't see why you use times tables to divide!
Some children do use short division, usually because their parents have shown them how to, but if I ask them to explain HOW it works, they are stumped!

11. minnieminxNew commenter

Short division is all very well, but it doesn't lead into long division (chunking) and so you still need to teach something else for longer division later.

We use a numberline in lower KS2 and for the lower sets in upper KS2. The upper set children in year 5 and 6 have no problems with chunking because they are familiar with the 'how many are in' idea from a numberline. They also don't move on to it until they are totally able to use their tables and multiples of, as well as subtract confidently.

We start with low numbers, move on to higher ones, move on to three digit by two digit and then by the end of year 6 any number including decimal is done quickly and easily.

Tis a joy to watch!

mimmiminx, just stop it!

LOLOL sorry!

14. minnieminxNew commenter

In my defence your post wasn't there when I wrote mine!

At least the times prove we aren't actually the same person!

probably just separated at birth

16. minnieminxNew commenter

LOL I've always known I was adopted really...and yeps definitely a twin.

17. alea

Have you considered chunking by complementary addition, basically chunking in reverse. So instead of starting with the dividend and subtracting the chunks you make the dividend from adding chunks. Skills needed are doubling, halving and multiplying by 10. I will try to do an example!
73 divide by 4
1x4=4
2x4=8
4x4=12
10x4=40
5x4=20
(start with 1x then double to get 2x and 4x, then x10 and half this to get x5)
pick the largest chunk to start
10x4=40
5x4=20 total 60
3x4=12 total 72
how many 4s = 18
r1
Can't set it out brilliantly but hopefully you get the idea. With larger dividends you use multiples of 10 (20x, 100x etc). I much prefer it, as traditional chunking relies heavily on subtraction (and compact subtraction at that) which allows many opportunities for error. Kids tend to be more accurate with addition. I did worry that we were dumbing down division (essentially turning it into multiplication) but I think so long as they understand the concept and can work it through that's the important thing.

18. minnieminxNew commenter

You can set out the above on a numberline which is what we do for ages, before introducing chunking. Definitely helps with the understanding.

19. Andrew JeffreyNew commenter

What a great thread! I too have worried about this for years, and agree with the point made about emphasising sharing too much at the expense of grouping. In fact there is some research to suggest that this is what shakes children's confidence with division, so I would always go with 'groups of' first.
The debate about chunking inevitably tends to be a bit of a 'marmite' one; I would like to suggest a middle ground (which may be what a previous poster has already said in which case ignore me!) about chunking UPWARDS from zero.
This is probably what most of us do in our heads (think about 6s into 70 for example and you probably go "10 of them is 60 and we can get another 1 in to make 66 so that's 11 with 4 left over."; chunking upwards.Just my 2p worth!

20. alea

I agree, Minnieminx. I would always begin with a number line and use the Grouping ITP which shows a really visual picture of grouping, however it always used to frustrate me that it grouped from zero and added, rather than starting from the dividend and subtracting! So, now it fits perfectly as it leads them seamlessly into additive chunking.