COUNT
Counts the number of cells that contain numbers and numbers within the list of arguments. Use COUNT to get the number of entries in a number field in a range or array of numbers.
Syntax
COUNT(value1,value2, ...)
Value1, value2, ... are 1 to 30 arguments that can contain or refer to a variety of different types of data, but only numbers are counted.
 Arguments that are numbers, dates, or text representations of numbers are counted; arguments that are error values or text that cannot be translated into numbers are ignored.
 If an argument is an array or reference, only numbers in that array or reference are counted. Empty cells, logical values, text, or error values in the array or reference are ignored. If you need to count logical values, text, or error values, use the COUNTA function.
Examples
In the following example,

A 
1 
Sales 
2 
12/8/90 
3  
4 
19 
5 
22/24 
6 
TRUE 
7 
#DIV/0! 
COUNT(A1:A7)
equals 3
COUNT(A4:A7)
equals 2
COUNT(A1:A7, 2)
equals 4