Over 40. 1 is not a prime number.
- Not a prime.
Over 40 and was taught that 1 is not prime even though some books may state differently.
1 was in a “unique class” and the fundamental theorem was mentioned at some point, although I don’t recall how much deeper the explanation went.
I ended up as an Engineer and a bit of a math geek. The idea of the process of proving something like the fundamental theorem kind of started my interest in higher math back in the day.
I think in elementary school we learned that 1 is “sort of” or “maybe” prime; there were some weasel words in there, at least.
I don’t recall what I was taught before college, but I was a math major, so I got a bunch of good explanations as to why one is not prime. The definition that’s usually taught is confusing; we should instead teach that primes are numbers which have exactly two distinct divisors. That makes it very clear that zero and one are not primes.
I learned about The Prime of Miss Jean Brodie in school.
Like 1 and -1? 
I don’t remember what, if anything, I was taught about this at school, but it has always seemed to me that that the notion that 1 is not a prime is a fudge. By any non-gerrymandered definition of primality, one is prime.
How do you think the classification of 1 as non-prime is “gerrymandered”?
I’m over 40, and there’s nothing for me to click. The only people who can click they were taught it’s *not *prime are under 20, and then only in college.
What the hell is wrong with you and your poll?
Huh, Euclid’s definition shows it’s more of a semantics issue, not really a math issue. I wish the people who contribute to wikipedia articles would learn to write more clearly. Even in modern English, there’s still a colloquial use of “number” to mean multiples. Thanks!
Possibly “gerrymandered” because the defintion boundry for both prime and composite are drawn around one. At least the Wiki defintions talk about integers greater than one. From that perspective it is not relevent to even talk about whether one is prime or composite because it is neither by defintion.
Over 60, and I learned one was not prime. I just checked algebra books from 1910, 1934, and 1955, and 1 is not prime in any of them, either.
Which is why I voted for banana pudding. I’m over 40 and was taught one was not prime nor will ever be prime.
That’s how I taught it to my seventh graders.
Over 40, and I remember that 1 was a special case - something like “while the only factors are 1 and itself like primes, it technically isn’t prime”
Brian
When I think back on all the crap I learned in high school…
Axiomatically not prime.
At first I was taught that 1 is “technically” not prime. The implication was that for most for the stuff we were doing, it shared enough properties with prime numbers that one could think of it that way, but it didn’t fully meet the definition. IIRC, the definition I was taught a few years later started with, “Any number other than 1 that can only be divided… etc yadda yadda.”
edit: I’m 34
I am over 40 (over 70, actually) and was certainly taught that 1 is not a prime. There are many formulas that would have special cases if 1 were called a prime.
First, a prime is a positive integer that has exactly 2 positive integer divisors. This is not actually the best definition, but it will do. Primes are the building blocks for numbers, just as atoms are he building blocks for molecules. Would you want to add an element #0 to the periodic chart that contains no protons, no neutrons and no electrons? Call it Z. Then the formula for water could be any of H2O, ZH2O, Z2H2O,… It would make exactly as much sense to say that 1 is a prime.
A better definition would also allow negative numbers and say that a number is prime if it is not invertible and any divisor is either invertible or an associate, where two numbers are associates if each divides the other (and then the quotients are invertible). This works in a wider area than just integers. For instance in Z*, the numbers of the form a+bi (i being a square root of -1), one can show that 1+i is prime, but -1+i, 1-i, and -1-i are all its associates. And all four divide 2, which is then not a prime in that domain.
Over 60 and was taught 1 is not prime (nor composite of course) in high or possibly middle school.
I’m over 40 and don’t remember what what primes I was taught in college. Oh the shame!