Apple iWork '09 - Manual (Page 197)

Chapter 8 Numeric Functions 197
Date/time values can’t be added together, so only one date/time value (as discussed Â
above) is permitted.
The values can be in individual cells, ranges of cells, or included directly as
Â
arguments to the function.
Examples
=SUM(A1:A4) adds the numbers in four cells.
=SUM(A1:D4) adds the numbers in a square array of sixteen cells.
=SUM(A1:A4, 100) adds the numbers in four cells plus 100.
Related Topics
For related functions and additional information, see:
“PRODUCT” on page 187
“Listing of Numeric Functions” on page 167
“Value Types” on page 36
“The Elements of Formulas” on page 15
“Using the Keyboard and Mouse to Create and Edit Formulas” on page 26
“Pasting from Examples in Help” on page 41
SUMIF
The SUMIF function returns the sum of a collection of numbers, including only
numbers that satisfy a specified condition.
SUMIF(test-values, condition, sum-values)
 test-values: The collection containing the values to be tested. test-values is a
collection containing any value type.
 condition: An expression that results in a logical TRUE or FALSE. condition is an
expression that can contain anything as long as the result from comparing condition
to a value in test-values can be expressed as a Boolean value of TRUE or FALSE.
 sum-values: An optional collection containing the numbers to be summed. sum-
values is a collection containing number, date/time, or duration values. It should
have the same dimensions as test-values.
Usage Notes
If  sum-values is omitted, the default value is test-values.
Although  test-values can contain any type of value, it should usually contain values
all of the same type.