Family Life How do you find the mean? How do you find the mean? The mean, or average, is calculated by adding up the scores and dividing the total by the number of scores. Related Posts:How Is the SAT Scored?, Choate Rosemary Hall Profile, and SAT Scores are some of the Frequently Asked Questions.GRE Score Range: What is a good score?I lost my act scores, please help!What is a good ISEE or SSAT Score?