5
5
It is not. Of the infinitely many primes only one (the number 2) is even, the rest are all odd. The sum of any two primes other than 2 is even and therefore not a prime. If one of the primes in the sum is 2 then the sum is a prime only if the other is the lower of a pair of twin primes. So, while it is possible, it is certainly more likely that the sum is a composite.
3 + 2 = 5 = 7 - 2
5 is the answer 2+3=5 7-2=5
There is no pair of prime numbers that sum to 123.Proof :Any two odd primes will sum to an even number, thus excluding 123 which is odd.Since 2 is the only even prime, the only possible solution is 2 + 121 = 123.But, 121 is not prime because it is 11 x 11.A similar proof shows that there is no pair of primes whose difference is 123.There are two primes that multiply to 123 : - 3 and 41.
Not true. 2 + 3 = 5, where all three are primes. One of the primes in the sum must be 2, otherwise both primes would be odd and their sum would be even (and >2) and therefore not prime. Such primes: p and p+2 [3 and 5 in the above example] are known as twin primes and there are infiitely many twin primes.
All prime numbers greater than 2 are odd numbers. For an odd prime to be written as the sum of two primes, one of the primes must be 2 because two odd primes will produce an even sum. 11 cannot be written as the sum of two primes. 13 = 2 + 11. 17 cannot be written as the sum of two primes. 19 = 2 + 17.
Are you asking The first prime that is the sum of three primes? I'll help. 2,3,5 are the first 3. the sum is 10. Not prime. now try 3,5,7. 15. Not prime. 5,7,11. 5,7,11 work, the sum is 23, which is a prime, not divisible by 2,3,4,5,6,7,8,9, so on. So the Three Primes are 5 7 11. The sum is 23.
5
For a 2-digit prime number (which are all odd) to be the sum of two prime numbers, one of the prime numbers will have to be 2. That means the difference between the sum and the other addend will have to be 2. Prime numbers that differ by 2 are called twin primes. There are six pairs of 2-digit twin primes. Your numbers are 13, 19, 31, 43, 61 and 73.
One.
2 + 3