2007-10-28 06:53:00 · 8 answers · asked by DEBBIE C 2 in Science & Mathematics ➔ Mathematics
2,3,5,7. the number 1 is not considered to be prime.
The reason mathematicians came up with a definition of prime number that excludes the number 1 is that many of the theorems about primes would be false otherwise.
for example, the fundamental theorem of arithmetic says that every positive whole number greater than one can be factored into primes in exactly one way, except for the order of the factors.
so, for example, if two different people were asked to factor the number 40, one might reason
40= 10x4=2x5x2x2
and the other might reason
40 = 8x5=2x2x2x5
These agree, except for the order of the prime factors. But if 1 were allowed to count as a prime, then we would have ininitely many different "prime" factorizations:
2x2x2x5x1
2x2x2x5x1x1
.
.
.
It's just too awkward to allow 1 to be a prime, so mathematicians agree, by "legislation" if you will, to not consider it a prime, simply for the sake of convenience.
2007-10-28 07:19:06 · answer #1 · answered by Michael M 7 · 0⤊ 0⤋
1 is not considered a prime number.
2 has no other factors except 2 and 1, so 2 is a prime.
Continue testing until you have enough prime numbers.
2007-10-28 13:57:45 · answer #2 · answered by DWRead 7 · 0⤊ 1⤋
2, 3, 5, 7
1 isnt considered a prime number
2007-10-28 13:56:26 · answer #3 · answered by citsymtserof 2 · 1⤊ 0⤋
1, 2, 3, 5,
2007-10-28 13:56:12 · answer #4 · answered by Scooter_The_Squirrels_Wifey 6 · 0⤊ 1⤋
2,3,5,7
1 is not a prime number because a prime number is only divisible by two numbers, itself and 1. 1 is only divisible by itself.
2007-10-28 14:03:45 · answer #5 · answered by Phantom 2 · 1⤊ 0⤋
1,2,3,5
2007-10-28 14:07:50 · answer #6 · answered by Anonymous · 0⤊ 0⤋
1,2,3,5
2007-10-28 13:57:45 · answer #7 · answered by gyro81 1 · 1⤊ 0⤋
1,2,3,5
2007-10-28 13:56:09 · answer #8 · answered by Hopelessly Devoted To You 4 · 0⤊ 1⤋