What is the difference between mass number and atomic mass?

Explanation

To answer the question "What is the difference between mass number and atomic mass?", we can break it down into a step-by-step explanation.

### Step-by-Step Solution:

1. **Definition of Mass Number**:
- Mass number is defined as the total number of protons and neutrons present in the nucleus of an atom.
- It is calculated using the formula:
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