Select an empty cell where you want the mean to appear
Type `=AVERAGE(range)`
Replace `range` with the cells containing your numbers, such as `=AVERAGE(A1:A10)`
Press Enter
Use the AutoSum drop-down and choose Average
Highlight the cells you want to average, then check the result in the status bar
Include multiple ranges if needed, such as `=AVERAGE(A1:A10,C1:C10)`
Ignore blank cells automatically
Use `=AVERAGEIF(range, criteria)` for a conditional mean
Use `=AVERAGEIFS(range, criteria_range1, criteria1, …)` for multiple conditions