Add the list of decimals. For example, consider the following list: 0.45, 1.6, 2.9 and 0.84. Added together, these values equal 5.79.
Count the number of decimals in the set that you added. In this example, you added four decimal figures.
Divide the total from Step 1 by the number of decimals in your set (as determined in Step 2). In this example, you would divide 5.79 by 4 to get 1.4475. This is the average for your set.