Why is weighted average is the best way to calculate the atomic mass?

The weighted average is the best method for calculating Atomic Mass because it accounts for the relative abundances of each isotope of an element. Since elements often exist as mixtures of isotopes, the weighted average reflects the contribution of each isotope based on its natural occurrence. This approach provides a more accurate representation of the element's mass as it considers both the mass of each isotope and its proportion in nature. Consequently, the calculated atomic mass closely aligns with the mass observed in real-world samples.