613

613

Author: Miryam Alter
Math Level: Prime Numbers
Grade Level: middle school
Topics: Prime numbers, square roots, factors, division

The Question:
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Is 613 a prime number?

The Answer:
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Yes it is prime.
You need only check odd numbers up to the closest square root of 613, namely 24.
Therefore – we will check – 3,5,7,9,11,13,15,17,19,21,23.
We can eliminate 3 because 6 + 1 + 3 = 10, the sum is not divisible by 3.  Therefore multiples of 3, namely 9, 15 and 21 cannot divide 613.
We can eliminate 5 because 613 does not end in a 0 or 5.
We can eliminate 11 because the of the way 11 works it would mean 613 is 63 x 11 which would be 693.
Therefore we have to check 13, 17, 19 and 23.  Using division, none of them are factors of 613.
Therefore, 613 is prime!
If it wasn’t – how many different divrei Torah would be composed trying to associate different miztvos with different factors.  613 is prime and therefore all miztvos are equal

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