Apple iWork '09 - Manual (Page 17)

Chapter 1 Using Formulas in Tables 17
Performing Instant Calculations in Numbers
In the lower left of the Numbers window, you can view the results of common
calculations using values in two or more selected table cells.
To perform instant calculations:
1 Select two or more cells in a table. They don’t have to be adjacent.
The results of calculations using the values in those cells are instantly displayed in the
lower left corner of the window.
The results in the lower left
are based on values in these
two selected cells.
sum: Shows the sum of numeric values in selected cells.
avg: Shows the average of numeric values in selected cells.
min: Shows the smallest numeric value in selected cells.
max: Shows the largest numeric value in selected cells.
count: Shows the number of numeric values and date/time values in selected cells.
Empty cells and cells that contain types of values not listed above aren’t used in the
calculations.
2 To perform another set of instant calculations, select different cells.
If you find a particular calculation very useful and you want to incorporate it into a
table, you can add it as a formula to an empty table cell. Simply drag sum, avg, or one
of the other items in the lower left to an empty cell. The cell doesn’t have to be in the
same table as the cells used in the calculations.