13 & 7
There is only one even prime number: 2. So, representing 20 as a sum of even prime numbers would be 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2.
2 + 3 = 5
If one of the two numbers is 2, the sum of two prime numbers may sometimes be a prime number. Examples of this are 2 + 11 = 13, 2 + 521 = 523, 2 + 281 = 283. There are an infinite number of similar examples where the sum of 2 plus a prime is another prime. However if neither number is 2, then the sum of two prime numbers is always an even number greater than 2 and therefore composite.
2 and 3.
2
111 + 1 = 2
There is only one even prime number: 2. So, representing 20 as a sum of even prime numbers would be 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2.
There is only one prime number and it is '2' You cannot have any other even prime number
The sum of two prime numbers greater than 2 is an even number. The sum of 2 and any other prime number is an odd number.
2 + 3 = 5
Factors for 20 are: 1, 2, 4, 5, 10, 20 Prime Factors: 2, 5 sum of prime factors = 2 + 5 = 7
There are not three prime numbers that have the sum of 3. The smallest prime number is 2. If all three prime numbers were 2, the sum would 2 + 2 + 2 = 6, so that is the smallest number that is the sum of three prime numbers.
2 + 3 = 5
The sum of any two prime numbers may or may not be prime. The sum of the two prime numbers 2 and 3 is the prime number 5, and the sum of the two prime numbers 5 and 7 is the composite number 12.
If one of the two numbers is 2, the sum of two prime numbers may sometimes be a prime number. Examples of this are 2 + 11 = 13, 2 + 521 = 523, 2 + 281 = 283. There are an infinite number of similar examples where the sum of 2 plus a prime is another prime. However if neither number is 2, then the sum of two prime numbers is always an even number greater than 2 and therefore composite.
2 and 3.
The prime factors are: 2 and 5 (2+5 = 7)