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Calling all maths experts for help with this please
https://www.elevenplusexams.co.uk/forum/11plus/viewtopic.php?f=2&t=58113
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Author:  worrybot [ Tue Jun 04, 2019 8:55 am ]
Post subject:  Calling all maths experts for help with this please

Please can any one explain how to solve this type of question?

1. Can you find numbers to replace A, B and C in this sum? (A,B and C are different numbers)

A B C
A B C
+ A B C
____________
B B B

2. Can you find a four digit number which is reversed when multiplied by 9? (i.e. ABCD X 9 = DCBA)

Author:  Qeb2019 [ Tue Jun 04, 2019 9:47 am ]
Post subject:  Re: Calling all maths experts for help with this please

I think q1 is not correct.

Q2. A has to be 1 otherwise any number time 9 will make 5 digits number. Therefore D is 9. B has to be 0 because any number times with 9 will have carry forward and make 5 digit number. And C is 8. The number is 1089.

Hope that helps.

Author:  worrybot [ Tue Jun 04, 2019 10:21 am ]
Post subject:  Re: Calling all maths experts for help with this please

Thank you for your help. I have the answer to Q1 and the question is correct. I am trying to understand a way to explain the solution to DS in a simplified way than trying to guess all possible outcomes.

Thank you

Author:  loobylou [ Tue Jun 04, 2019 10:34 am ]
Post subject:  Re: Calling all maths experts for help with this please

With question 1, this is how I did it but I am not a maths teacher and I don't know if there is a better way to teach/explain it.
BBB has to be divisible by 3 as ABC X 3 = BBB.
You can rule out 999, 666 and 333 because they don't give an ABC answer. You can rule out 111 because that wouldn't give a 3 figure answer.
So I started to do 222÷3, 444÷3, 555 ÷3 etc until I got to the number that had the middle number the same as the B.
Hope that makes sense.

Author:  worrybot [ Tue Jun 04, 2019 10:40 am ]
Post subject:  Re: Calling all maths experts for help with this please

Quote:
Hope that makes sense.


Yes it does make perfect make sense.

Thank you so much

Author:  Qeb2019 [ Tue Jun 04, 2019 10:56 am ]
Post subject:  Re: Calling all maths experts for help with this please

worrybot wrote:
Thank you for your help. I have the answer to Q1 and the question is correct. I am trying to understand a way to explain the solution to DS in a simplified way than trying to guess all possible outcomes.

Thank you


Sorry I’m wrong. Tried to do in my head. Loobylow gave perfect answer.

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