A Direct Attempt to Goldbach Problem

The so-called "principal term of Goldbach problem, i.e.. the principal order of the number of representations of an even number as a sum of two primes, is evaluated here in a way quite different from the classical circle method. It is amazing that the author did this with the knowledge just at the PNT (Prime Number Theorem) level, even without using high-level theorems in analytic number theory as usual, c.g., Siegel-Walfisz Theorem.