# Atomic Mass Number Calculator

## Atomic Mass Number Formula

The formula to calculate the Atomic Mass Number (\(A\)) is:

\[ A = Z + N \]where:

- \( A \) is the Atomic Mass Number,
- \( Z \) is the Number of Protons in the atom, and
- \( N \) is the Number of Neutrons in the atom.

Calculate the Atomic Mass Number (\(A\)) for an atom with \(Z = 20\) (number of protons) and \(N = 25\) (number of neutrons).

**Answer:**

Using the Atomic Mass Number formula:

\[ A = 20 + 25 = 45 \]Therefore, the Atomic Mass Number (\(A\)) is 45.