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Re: NS Doubt
by TG Team - Friday, 13 July 2012, 06:47 AM
 

Hi smile

For 7: make group of three digits together starting from unit digit side and make them alternate positive and negative with first group from unit digit side being positive. For example: 2123456789 = (-2 + 123 - 456 + 789) mod7 = 454 mod7 = 6 mod7.

For 37: make group of three digits together starting from unit digit side and all groups are positive. For example: 20103321 = (20 + 103 + 321) mod37 = 444 mod37 = 0 mod37.

Hope it is clear now. smile

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Re: NS Doubt
by tgdel678 tg - Friday, 13 July 2012, 06:55 PM
  Kamal Sir,

I am sorry but kindly throw some light on how should I divide N by 32..
How can it be done using the Euler's Totient function according to which, a digit repeated N-1 times is divisible by N where N is a prime number ??
Kindly share any other approach as well, if any..

Thank you.. smile
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Re: NS Doubt
by TG Team - Friday, 13 July 2012, 08:03 PM
 

Hi tgdel678 tg smile

First 32 is not a prime number, so you can't use the method you mentioned.

Now 32 = 25 and recall that remainder when any number, N is divided by 2n is same as the remainder obtained by dividing number formed by last n-digits of N by same divisor 2n.

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Re: NS Doubt
by tgdel678 tg - Friday, 13 July 2012, 09:55 PM
  Wonderful Sir, I didn't knew that before.. Thanks a lot.. smile
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Re: NS Doubt
by tgdel678 tg - Friday, 13 July 2012, 09:57 PM
  Sir,

Can it be done using this Euler's method also mentioned above by me ?? If so, how ??

Thank you.. smile
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Re: NS Doubt
by anila . - Sunday, 15 July 2012, 07:11 AM
  Hello sir
can you plz explain "remainder when any number, N is divided by 2n is same as the remainder obtained by dividing number formed by last n-digits of N by same divisor 2n" with an example
thank u
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Re: NS Doubt
by TG Team - Sunday, 15 July 2012, 04:34 PM
 

Hi Anila smile

It is 2n not 2n.

If you want to check whether N is divisible by 4 (22) or not, just check the number formed by last 2 digits.

If you want to check whether N is divisible by 8 (23) or not, just check the number formed by last 3 digits.

If you want to check whether N is divisible by 164 (24) or not, just check the number formed by last 4 digits.

Similarly If you want to check whether N is divisible by 2n or not, just check the number formed by last n digits.

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