1. **State the problem:** We want to understand why $1 + 1$ equals $2$. 2. **Define the numbers:** The number $1$ represents a single unit or object. 3. **Addition meaning:** Adding $1 + 1$ means putting together one unit and another unit. 4. **Count combined units:** When we combine one unit and another unit, we count them as two units in total. 5. **Formal mathematical view:** In the Peano axioms, $2$ is defined as the successor of $1$, so adding $1 + 1$ is moving to the successor of $1$, which is $2$. 6. **Conclusion:** Therefore, $1 + 1 = 2$ because adding one unit to another unit results in two units.