# Talk

## Y4 compact multiplication of double digits

(12 Posts)
GeneGreenie Sun 29-Nov-15 21:44:40

So for example 84x56

Ds has just started to progress with the compact method at school and we've been encouraged to help at home. He's confident in the double X single digit 14x8 for example and he's fine doing the expanded method (or whatever it's called) but I'm finding it hard to explain the above sum.

He can easily do 84x6, it's when you then move across to the left that he's slightly puzzled with how it works, my method is you put a zero first as this helps when you add the two together, im presuming school don't add this zero?

I think he'll get there in the end but I don't want him to become confused with different methods.

Is this what they should be learning in Y4?

GeneGreenie Sun 29-Nov-15 21:47:33

84
56
504
4200 < this zero is confusing him
4704

falgelednl Sun 29-Nov-15 22:11:44

Explain that the reason you need to put in the zero is because when multiplying by the 5 it is actually 50. Putting in the zero moves everything up one column to the left - which is the result when multiplying by a multiple of 10. Once the zero is in place, you can just multiply by 5. Does that help?

GeneGreenie Sun 29-Nov-15 22:17:29

I'm sorry, I'm very rusty with maths and I just did it this way at school without fully understanding why, which doesn't help me when trying to explain it to Ds. I'm not good at explaining where maths is concerned.

It seems that this hasn't sunk in at school yet, surely homework should just be an extension of what's been taught at school but we have been asked to help out at home. This is ok if you're confident explaining, which I'm not.

GeneGreenie Sun 29-Nov-15 22:18:40

Thanks for your response though. I will see if this helps.

I'm not sure he's ready to move to this yet.

irvine101 Sun 29-Nov-15 22:33:48
GeneGreenie Sun 29-Nov-15 23:33:02

Irvine, thank you, that will help greatly and has a far better explanation.

GeneGreenie Mon 30-Nov-15 07:04:42

I'm embarrassed by how thick I sound on this thread, enough that I'll be name changing.

I don't see patterns in numbers I just do a sum the way I was taught, I don't think of why I do something ie, the zero, I just do it. Now you've explained it makes sense I look at numbers on a page and they honestly mean nothing to me, if there was a dyslexia for maths I think I'd have some form of it.

Maths scares me, I'm hoping I won't pass this onto Ds, dread it when he brings maths homework home even in Y4. Quite sad really.

noblegiraffe Mon 30-Nov-15 07:10:51

Dyslexia for maths is called dyscalculia. en.m.wikipedia.org/wiki/Dyscalculia

Have a look at the symptoms to see if it fits.

GeneGreenie Mon 30-Nov-15 07:19:48

Thanks Noble, I'll take a look.

irvine101 Mon 30-Nov-15 07:29:12

I struggle explaining to my ds as well.

This khan website is very handy, it has tutorials for most maths skills.
Just choose subject(maths) and type the topic and search at the top of the page.

GeneGreenie Mon 30-Nov-15 07:45:15

Thanks so much, Irvine. Your link certainly helped me with regards to the explanation. I will definitely be referring back to it with Ds. He's doing very well in Maths (obviously doesn't take after me, or his father come to that) which is why I don't want to get these early years wrong, which is probably what happened in my case.

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