In Sheets you can quickly calculate things using formulas so you do not have to spend a lot of time working these out yourself.

1) Click in the cell you want to use

2) It is a good idea to use labels to show what you are calculating (e.g. TOTAL, AVERAGE etc)

3) A formula always starts with = and has NO SPACES

4) The Machine Learning in Google will offer suggestions, you can click TAB or click the suggestion to accept it or you can type your own

5) You can SELECT the cells with the data you want to use or you can type them in separated by a colon :

6) Here are some formulas you can use (there are LOADS MORE)

=SUM(B2:B9) to calculate the total

=AVERAGE(C2:C9) to calculate the average or mean

=MEDIAN(B2:B9) to calculate the middle number of sorted data

=MODE(C2:C9) to calculate the number that shows up the most

Check out the screencast below to see how this works