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# Just to refresh basic divisibility rules... A number is

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Intern
Joined: 24 Sep 2008
Posts: 18
Just to refresh basic divisibility rules... A number is [#permalink]

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09 Oct 2008, 02:52
1
Just to refresh basic divisibility rules...

A number is divisible by 2: unit digit is even i.e 128, 146 44 etc. (tough one)

A number is divisible by 3: sum of digits is divisible by 3 i.e 102, 192, 99 etc

A number is divisible by 4 when the number formed by last two right hand digits is divisible by '4' i.e. 576, 144

A number is divisible by 5 when its uni digit is either five or zero: e.g. 11155, 3970, 145 etc.

A number is divisible by 6 when it is divisible by 2 & 3 both e.g 714, 509796, 1728 etc.

A number is divisible by 8 when the number formed by the last three right hand digits is divisible by 8 i.e. 512, 4096, 1304

A number is divisible by 9 when the sum of its digits is divisible by 9 e.g. 1287, 11583, 2304 etc.

A number is divisible by 11 when the difference between the sums of digits in the odd and even places is either zero or a multiople of 11 i.e 17259, 62468252, 12221 etc.
For the number 17259: sum of digits in even places = 7+5 = 12, Sum of digits in the odd Places = 1+2+9=12
hence 12-12 =0 So the number is divisible by 11.

Thanks.

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VP
Joined: 30 Jun 2008
Posts: 1008
Re: Very Basic Divisiblity rules [#permalink]

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09 Oct 2008, 03:08
kam wrote:
Just to refresh basic divisibility rules...

A number is divisible by 2: unit digit is even i.e 128, 146 44 etc. (tough one)

A number is divisible by 3: sum of digits is divisible by 3 i.e 102, 192, 99 etc

A number is divisible by 4 when the number formed by last two right hand digits is divisible by '4' i.e. 576, 144

A number is divisible by 5 when its uni digit is either five or zero: e.g. 11155, 3970, 145 etc.

A number is divisible by 6 when it is divisible by 2 & 3 both e.g 714, 509796, 1728 etc.

A number is divisible by 8 when the number formed by the last three right hand digits is divisible by 8 i.e. 512, 4096, 1304

A number is divisible by 9 when the sum of its digits is divisible by 9 e.g. 1287, 11583, 2304 etc.

A number is divisible by 11 when the difference between the sums of digits in the odd and even places is either zero or a multiople of 11 i.e 17259, 62468252, 12221 etc.
For the number 17259: sum of digits in even places = 7+5 = 12, Sum of digits in the odd Places = 1+2+9=12
hence 12-12 =0 So the number is divisible by 11.

Thanks.

Nice post ... But isn't it weird that there have been only 3 visits and no replies to this post but 12 KUDOS

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"You have to find it. No one else can find it for you." - Bjorn Borg

Intern
Joined: 24 Sep 2008
Posts: 18
Re: Very Basic Divisiblity rules [#permalink]

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09 Oct 2008, 04:13
hmmm visits are more than kudos but it still seems weird.. can someone give multiple kudos during one visit ?

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: Very Basic Divisiblity rules   [#permalink] 09 Oct 2008, 04:13
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# Just to refresh basic divisibility rules... A number is

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