The result of $1 + 2$ is $3$.

Would you like more details or have any other questions?

Here are some related questions:

1. What is $3 + 4$?
2. How do you add fractions like $\frac{1}{2} + \frac{1}{3}$?
3. What is the commutative property of addition?
4. Can you add negative numbers? (e.g., $-1 + 2$)
5. How do you solve word problems involving addition?

Tip: Always remember that addition is one of the fundamental arithmetic operations and forms the basis for many other concepts in mathematics.