71 and 103 is one of infinitely many pairs.
43
420 has four prime factors. Prime factors don't usually travel in pairs.
There are two pairs of prime numbers that express 18 as the sum of two prime numbers: 7 + 11 = 18 and 5 + 13 = 18.
There are three pairs.
6
There are 35 pairs of twin prime numbers totaling 69 numbers (prime number 5 appears twice in the twin pairs) between 0 and 1000.
41,2
7
One. 997 and 2
Eight pairs.
Only one pair.