How do you calculate the average of the numbers 3, 5, 7, and 9?

To find the average of a set of numbers, you first add all the numbers together and then divide the total by the count of the numbers in the set. In this case, you have the numbers 3, 5, 7, and 9.

First, you sum these numbers:

3 + 5 + 7 + 9 = 24.

Then, since there are 4 numbers in total, you divide the sum by 4:

24 ÷ 4 = 6.

So, the average of the numbers 3, 5, 7, and 9 is 6. This method of adding the numbers and then dividing by the count is the standard approach for calculating an average (mean).

The other methods described in the choices do not accurately reflect how to compute an average. Multiplying or dividing in the suggested ways would not yield the correct average of the values provided.