What is the sum of the numbers 1, 2, and 3?

To find the sum of the numbers 1, 2, and 3, you simply add these values together.

Starting with the first two numbers:

1 + 2 equals 3.

Now, take this result and add the next number:

3 + 3 equals 6.

Thus, the total sum of 1, 2, and 3 is 6, making it the correct choice.

This straightforward addition illustrates the basic principle of summation where individual values are combined to find a total. Understanding this foundational concept in mathematics is essential for solving more complex problems in the future.