DAVERAGE

Averages the values in a column of a list or database that match conditions you specify.
Syntax
DAVERAGE(database,field,criteria)
Database    is the range of cells that makes up the list or database. A database is a list of related data in which rows of related information are records, and columns of data are fields. The first row of the list contains labels for each column.
Field    indicates which column is used in the function. Field can be given as text with the column label enclosed between double quotation marks, such as "Age" or "Yield," or as a number that represents the position of the column within the list: 1 for the first column, 2 for the second column, and so on.
Criteria    is the range of cells that contains the conditions you specify. You can use any range for the criteria argument, as long as it includes at least one column label and at least one cell below the column label for specifying a condition for the column.

Example
The example may be easier to understand if you copy it to a blank worksheet.

	A	B	C	D	E
1	Tree	Height	Age	Yield	Profit
2	Apple	>10
3	Pear
4	Tree	Height	Age	Yield	Profit
5	Apple	18	20	14	105.00
6	Pear	12	12	10	96.00
7	Cherry	13	14	9	105.00

COUNTBLANK

Counts empty cells in a specified range of cells.
Syntax
COUNTBLANK(range)
Range    is the range from which you want to count the blank cells.
Remark
Cells with formulas that return "" (empty text) are also counted. Cells with zero values are not counted.
Example
The example may be easier to understand if you copy it to a blank worksheet.

	A	B
1	Data	Data
2
3	6	=IF(B4<30,"",B4)
4		27
5	4	34

Formula	Description (Result)
=COUNTBLANK(A2:B5)	Counts empty cells in the range above. The formula returns empty text. (4)

HOUR

Returns the hour of a time value. The hour is given as an integer, ranging from 0 (12:00 A.M.) to 23 (11:00 P.M.).
Syntax
HOUR(serial_number)
Serial_number    is the time that contains the hour you want to find. Times may be entered as text strings within quotation marks (for example, "6:45 PM"), as decimal numbers (for example, 0.78125, which represents 6:45 PM), or as results of other formulas or functions (for example, TIMEVALUE("6:45 PM")).
Remark
Microsoft Excel for Windows and Excel for the Macintosh use different date systems as their defaults. Time values are a portion of a date value and represented by a decimal number (for example, 12:00 PM is represented as 0.5 because it is half of a day).
Example
The example may be easier to understand if you copy it to a blank worksheet.

	A
1	Time
2	3:30:30 AM
3	3:30:30 PM
4	15:30

Formula	Description (Result)
=HOUR(A2)	Hour of first time (3)
=HOUR(A3)	Hour of second time (15)
=HOUR(A4)	Hour of third time (15)

COS

Returns the cosine of the given angle.
Syntax
COS(number)
Number    is the angle in radians for which you want the cosine.
Remark
If the angle is in degrees, multiply it by PI()/180 or use the COS function to convert it to radians.
Example
The example may be easier to understand if you copy it to a blank worksheet.

	A	B
1	Formula	Description (Result)
2	=COS(1.047)	Cosine of 1.047 radians (0.500171)
3	=COS(60*PI()/180)	Cosine of 60 degrees (0.5)
4	=COS(RADIANS(60))	Cosine of 60 degrees (0.5)

DAY

Returns the day of a date, represented by a serial number. The day is given as an integer ranging from 1 to 31.
Syntax
DAY(serial_number)
Serial_number    is the date of the day you are trying to find. Dates should be entered by using the DATE function, or as results of other formulas or functions. For example, use DATE(2008,5,23) for the 23rd day of May, 2008. Problems can occur if dates are entered as text.
Remarks
Microsoft Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900. Microsoft Excel for the Macintosh uses a different date system as its default.
Values returned by the YEAR, MONTH and DAY functions will be Gregorian values regardless of the display format for the supplied date value. For example, if the display format of the supplied date is Hijri, the returned values for the YEAR, MONTH and DAY functions will be values associated with the equivalent Gregorian date.
Example
The example may be easier to understand if you copy it to a blank worksheet.

	A
1	Date
2	15-Apr-2008

Formula	Description (Result)
=DAY(A2)	Day of the date above (15)

DATEVALUE

Returns the serial number of the date represented by date_text. Use DATEVALUE to convert a date represented by text to a serial number.
Syntax
DATEVALUE(date_text)
Date_text    is text that represents a date in a Microsoft Excel date format. For example, "1/30/2008" or "30-Jan-2008" are text strings within quotation marks that represent dates. Using the default date system in Excel for Windows, date_text must represent a date from January 1, 1900, to December 31, 9999. Using the default date system in Excel for the Macintosh, date_text must represent a date from January 1, 1904, to December 31, 9999. DATEVALUE returns the #VALUE! error value if date_text is out of this range.
If the year portion of date_text is omitted, DATEVALUE uses the current year from your computer's built-in clock. Time information in date_text is ignored.
Remarks

• Excel stores dates as sequential serial numbers so they can be used in calculations. By default, January 1, 1900 is serial number 1, and January 1, 2008 is serial number 39448 because it is 39,448 days after January 1, 1900. Excel for the Macintosh uses a different date system as its default.
• Most functions automatically convert date values to serial numbers.