not sure how to find this...

Find the number of ordered pairs of primes (p,q) such that p+q=1003.

 

Well it seems to me that the only even prime number is 2

and

the only way 2 numbers can add to get a odd number is if one is even and one is odd.

 

so the only possible answer is  2 and 1001

that is assuming of course that 1001 is prime - I shall use the web 2 calc to help with that.

 

factor(1001) = (7*11)*13

so 1001 is not prime.

 

So there are no prime numbers that add to 1003

Mmm i wonder if negative numbers can be prime. - Well not under the usual definition of primes they can't.

 

Ok I do not believe that there is an ordered pair that satisfies this condition :)