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PostPosted: Mon Jul 04, 2011 1:40 pm 
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Joined: Wed May 25, 2011 10:36 pm
Posts: 35
Hello all hope you can help my child is struggiing with the following

(4[12]36) (2[6]18) (5[?]45)
answer is 15

(14[15]17) (2[5]9) (8[?]23)

answer is15

Look forward to hearing from you and many thanks.


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PostPosted: Mon Jul 04, 2011 1:56 pm 
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Joined: Mon Mar 15, 2010 2:45 pm
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I think the first one is simple multiples of 3, and the second one seems to be doubling the amount taken off the last figure, but I'm not expert, I just happened to see your post!! :lol: :roll:


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PostPosted: Mon Jul 04, 2011 2:02 pm 
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Joined: Tue May 10, 2011 1:12 pm
Posts: 113
Hi aaman1,

I know how to do the first one, but am struggling with the 2nd one. Will try to get the answer from my DD if she can solve it.

(4[12]36) (2[6]18) (5[?]45)

4 X 3 = 12 X 3 = 36, therefore the number in brackets being 12
2 x 3 = 6 x 3 = 18, therefore the number in brackets being 6
5 x3 = 15 x 3 = 45, therefore teh number in brackets being 15

So the common number being used for multiplying is "3"

Hope this helps.


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PostPosted: Mon Jul 04, 2011 2:05 pm 
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Joined: Mon Jan 30, 2006 4:07 pm
Posts: 2660
(4[12]36) (2[6]18) (5[?]45)
answer is 15


4 x 36 = 144
144 divided by 12 [number on left x 3] = 12

18 x 2 = 36
36 divided by 6 [number on the left x 3] = 6

45 x 5 = 225
225 divided by 15 [number on the left x 3] = 15

or

4 x 36 = 144
144 divided by 12 [the number on the right divided by 3] =12

2 x 18 = 36
36 divided by 6 [number on the left divided by 3] = 6

45 x 5 = 225
225 divided by 15 [number on the right divided by 3] = 15


(14[15]17) (2[5]9) (8[?]23)
answer is15


Not got time to work out at the moment, dashing out. Are the numbers correct?

Patricia


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PostPosted: Mon Jul 04, 2011 3:37 pm 
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Joined: Wed Jan 11, 2006 7:10 pm
Posts: 8200
Location: Buckinghamshire
aaman1 wrote:
(14[15]17) (2[5]9) (8[?]23)

answer is15
Number two is as follows:

14 + 17 = 31
31 - 1 = 30
30 / 2 = 15

2 + 9 = 11
11 - 1 = 10
10 / 2 = 5

8 + 23 = 31
31 - 1 = 30
30 / 2 = 15

Hope that helps.


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PostPosted: Mon Jul 04, 2011 3:45 pm 
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Joined: Mon Mar 15, 2010 2:45 pm
Posts: 4604
Goodness me, and we expect children who are just 10 to be able to do that!! :oops:


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PostPosted: Mon Jul 04, 2011 7:37 pm 
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Joined: Mon Jan 30, 2006 4:07 pm
Posts: 2660
As I did not have time to write up the answer earlier, I took it with me to my lessons this evening, the children "got it" straight away. Once children know the basic method and techniques and as long as they work logically, they will always find the answer.

There have been a few examples of using 3 operations instead of the bog standard 2. I try teach my children all possibilities.

Patricia


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PostPosted: Wed Jul 13, 2011 10:46 am 
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Joined: Wed May 25, 2011 10:36 pm
Posts: 35
Thanks everyone so much.................


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