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Simple composite number (Posted on 2023-07-26)

Show that the number 9999999+1999000 is composite.

No Solution Yet Submitted by Danish Ahmed Khan

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Puzzle Solutio

| Comment 1 of 3

9999999+1999000

= 10^7-1+( 2000--1)*1000

= 10^7 +2*10^6 -10^3-1

= 12*10^6 -10^3-1

= 12*10^6+3*10^3-4*10^3 -1

= 3*10^3(4*10^3 +1) -1(4*10^3+1)

= (4*10^3+1)(3*10^3-1)

=4001 * 2999

Therefore, the given sum must be composite.

Edited on July 26, 2023, 8:46 am

Posted by K Sengupta on 2023-07-26 08:13:27

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