Multiplying decimals

11 Plus Maths – Preparation and Information

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mh1
Posts: 100
Joined: Thu Feb 21, 2008 10:48 pm

Multiplying decimals

Post by mh1 »

Can anyonew advise the best/simplist technique to teach a young child on multiplying decimals e.g. 0.62*0.53
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Post by Guest55 »

Use grid multiplication on 62 x 53 each number is 100 times bigger so the answer will need to be divided by 10000.


0.62 x 0.53


What level is your child working at?
mh1
Posts: 100
Joined: Thu Feb 21, 2008 10:48 pm

Post by mh1 »

Guest 55

Thank you for the response.

Thats the tecnique I had in mind - was wandering whether theres any other easier methods?

My child is KS2 level
Guest55
Posts: 16254
Joined: Mon Feb 12, 2007 2:21 pm

Post by Guest55 »

This is quite high level so I don't think there is an easier way.
katel
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Joined: Thu Jan 11, 2007 11:30 pm

Post by katel »

I don't think they do multiplying decimals in KS2.
perplexed
Posts: 490
Joined: Wed Jan 02, 2008 1:18 pm
Location: kent

Post by perplexed »

Well I'm not 100% sure whether multiplying decimals is in the KS2 syllabus or not (anyone have a good link through to the definitive KS2 maths syllabus?) but I have seen it in commercially available KS2 revision guides.

But, Katel, if it is definitely not in the KS2 syllabus what is your advice for a parent of a child sitting a selective entry exam which definitely will require some kind of understanding of this?
Mike
Posts: 625
Joined: Thu Jan 12, 2006 4:29 pm

Post by Mike »

Hi

0.62 x 0.53

First, ignore the decimal points.

Giving 62 x 53

Breakdown the sum into two parts

62 x 50 = 3100

62 x 3 = 186

Add the sum of both parts together

3286

Go back to the original sum and count how many numbers there are on the right of the decimal point, there are two numbers for each part of the sum, making four in total.

From the right hand side of 3286 count four places to the left and insert a decimal point giving .3286. I prefer 0.3286.

Regards

Mike
Mike Edwards is a co-author of The Tutors product range.
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