SOLUTION: 99 consecutive natural numbers, all of which are composite. What is the smallest number in this set? 100!+2 What is the largest number in this set? 100!+100 What is the meth

Algebra ->  Divisibility and Prime Numbers  -> Lessons -> SOLUTION: 99 consecutive natural numbers, all of which are composite. What is the smallest number in this set? 100!+2 What is the largest number in this set? 100!+100 What is the meth      Log On


   



Question 1194081: 99 consecutive natural numbers, all of which are composite.
What is the smallest number in this set? 100!+2
What is the largest number in this set? 100!+100
What is the method to calculate this? Are my answers correct? Thanks

Answer by ikleyn(52776) About Me  (Show Source):
You can put this solution on YOUR website!
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99 consecutive natural numbers, all of which are composite.
What is the smallest number in this set? 100!+2
What is the largest number in this set? 100!+100
What is the method to calculate this? Are my answers correct? Thanks
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            Your answers are incorrect.

            I will construct a sequence of much smaller 99  consecutive natural number,  all of which are composite.


First consider all prime numbers lesser than 100:

    2, 3, 5, 7, 11, 13, 17, . . . , 89, 97.


Take each of them in maximum degree in a way it is still lesser tnan 100:

    2^6 = 64;  3^4 = 81;  5^2 = 25;  7^2 = 49;  11, 13, 17, . . . , 89, 97.


Take the product of these numbers

    N = 2%5E6%2A3%5E4%2A5%5E2%2A7%5E2%2A11%2A13%2A17%2A+ellipsis+%2A+89%2A97.


Then 99 consecutive natural numbers

    N+2, N+3, N+4, N+5, . . . , N+99, N+100


are 

        (a)  all composite 

    and 

        (b)  these numbers are less than yours.



Notice, that I do not state that this sequence is minimal; but in any case, it is lesser than yours.

Similar reasoning works for your second question.