The sum of $3 + 3$ is $6$.

Would you like further details or have any questions?

Here are some related questions:

1. What is $3 \times 3$?
2. What is $6 - 3$?
3. If you add $3$ three times, what do you get?
4. How would you express $3 + 3$ using multiplication?
5. What is the sum of $3 + 3 + 3$?

Tip: When adding two numbers, the order doesn't matter (commutative property).