The sum of $1 + 1$ is:

$1 + 1 = 2$

Would you like more details or have any questions?

Here are 5 related questions to expand on this:

1. What is $2 + 2$?
2. What is $5 - 1$?
3. How do you add two numbers with decimals, like $1.5 + 2.3$?
4. What is $1 + 1$ in binary?
5. Can you explain the concept of addition for larger numbers?

Tip: When adding numbers, the order in which you add them does not affect the result, this is known as the commutative property of addition.