Quick Q re KS2 maths techniques

[NottsCounting]

The following technique :
456
x7
--
42
350
2800
--
=3192

When is it normally taught at Junior School? It seems very straightforward and logical to me, much more so than the grid method...

[NottsCounting]

Second thoughts - maybe I should bump this later when some teachers might be around ? Unless anyone else knows?

[Scholes34]

Don't think it is, despite being logical and straightforward. We had a Maths (KS1 and 2) and and English (KS1) open evening at school which was really useful. It was an opportunity for us to learn what techniques are taught. Could be worth mentioning to your head.

[crazygracieuk]

I think the grid method is taught so that children understand what the 457 really means rather than learning how to do longer multiplication automatically.
My dd is in year 3 and would do it like you set out. (grid method) My ds in y5 would do it how we learned at school- 6x7 is 2 carry 4, 5x 7+4 is 9 carry 3 and so on.

[NottsCounting]

Ta for replies.
After a quick google, I have found out the way I have described is the 'vertical expanded method', which is apparently a step after the grid method? The only tricky bit is the carrying over, which you don't have to do in the grid method...hmm.

[crazygracieuk]

I think that the only difference between your method and the grid method is that you didn't explain what each line of your working out means.

[Feenie]

That's what I was going to say - it's the same as the grid method, except it isn't in a grid. It's called expanded multiplication, and comes after the grid method, when children have a thorough understanding of place value.


If you jumped straight to this list method, then it would be trickier to do, say, 2digits x 2 digits - the grid method ensures everything is multiplied by everything else, otherwise there are empty boxes, so it's obvious when a step is missed. Jumping straight to the expanded method might make that process harder.

[Feenie]

Ah sorry, I didn't see your last post where you had worked out what it was called and when it's learnt. Hope I answered your last hmmm!

[NottsCounting]

Aha - experts! Thank you both.
So, is it reasonable to expect my dc's to be using this method then? Yrs 3 and 5, and both strong at maths...

[Feenie]

I teach Y5 - strong mathematicians would use short multiplication (traditional column method). I'd teach the grid method to a good mathematician in Y3.

[NottsCounting]

Short multiplication? Is that what we adults do, with the results of a 3 digit x 1 digit sum in one line, no breakdowns? What about 3 digit x 2 digit sums - that would be two lines of results then added together, yes?
DD1 is still using the grid method at school, but I showed her the other way and she agreed it was much less hassle! DD2 then had a go, and was fine. She is using the grid method at school too. Both are top sets - should they be moving on by now as they both seem pretty secure in their tables and place values, at least to 4 digits? Ta!

[Feenie]

Yes, and yes!
If your dds are confident with the grid method and understand it, then the expanded method is the next step.

It depends on your school's calculation policy as to when they decide to move kids on; you could ask to see a copy. I would definitely expect your top set Y5 dd to be using at least that, if not short multiplication. Perhaps their policy asks for this method to be taught in Y6?

[NottsCounting]

Who knows about school policy lol! We are very much encouraged to leave them to it tbh. I know they have been multiplying fractions, and converting decimals to fractions and percentages, plus starting with algebra. Does that sound about right, or should they be 'further' on by now?

NB, while I think the multiplication thing is a bit odd and slow-paced, I am sure I wasn't doing algebra and multiplying with fractions and decimals till senior school (though that is going back 30 years ). However, there is an ongoing issue, as raised by Ofsted, that the school are a bit complacent about the learning of the more able children. Another hmm...

PS Sorry for so many questions Feenie. It must get quite wearisome for you, so I am grateful!

[Feenie]

Whereas I don't think it's the best idea to leave formal methods exclusively until Y6, the most important thing is that they do have some kind of method at their fingertips, and can use it with confidence. So there may be a slight issue with slower teaching of a variety of methods to more able children, at least they are teaching something.

The rest of the teaching sounds about right, tbh.

I don't mind the questions!

[NottsCounting]

That is reassuring Feenie, thank you.
You must be a patient sort (Yr 5 during the day and ruminating MN parents at night lol!)

[RoadArt]

I showed our teacher the grid method recently (learnt from the web) and she had never heard of it. - frightening!