15 = 5 + 5 + 5
which are three primes, but
15 = 2 + 3 + 10
which are not. The theorem says there there is such a sum, not that all sums are of that form.
15 = 5 + 5 + 5
which are three primes, but
15 = 2 + 3 + 10
which are not. The theorem says there there is such a sum, not that all sums are of that form.