How do you get the mean of a data set?

Add together all the number in the data set.
Count the number of numbers in the data set.
Divide the sum by the number of values. That is the (arithmetic) mean.
If a question simply asks for the mean, it is referring to the arithmetic mean.

To find the geometric mean, count up the number of numbers in the data set and call than n. Multiply all the numbers together and take the nth root.