VBA includes several builtin operators and functions, which can be used for building expressions and quickly performing basic tasks in your VBA code.
The builtin VBA operators consist of mathematical operators, string operators, comparison operators and logical operators. The different types of Operators are discussed individually below.
The main Mathematical VBA operators are listed in the table below.
The precedences that are listed alongside the operators are the defaults, which are applied in the absence of brackets. However, the order in which the VBA operators are applied can be controlled by adding brackets to an expression:
Operator  Action  Precedence (1=top; 5=bottom) 

^  The power operator  1 
*  The multiplication operator  2 
/  The division operator  2 
\  The integer division operator (divides two numbers and returns the integer result  e.g. 7\4 gives a result of 1)  3 
Mod  The modulus operator (divides two numbers and returns the remainder  e.g. 8 Mod 3 gives a result of 2)  4 
+  The addition operator  5 
  The subtraction operator  5 
The concatenate operator & can be used to join together strings:
Operator  Action 

&  The concatenate operator (e.g. "A" & "B" gives the result "AB") 
Comparison operators compare two numbers or strings and return a logical (True or False) result. The main Excel VBA comparison operators are listed in the table below:
Operator  Action 

=  Equal To 
< >  Not Equal To 
<  Less Than 
>  Greater Than 
<=  Less Than or Equal To 
>=  Greater Than or Equal To 
Logical operators also return a logical (True or False) result. The main Excel VBA logical operators are listed in the table below:
Operator  Action 

And  Logical Operator And (e.g. the expression 'A And B' returns True if BOTH A AND B are true and returns False otherwise) 
Or  Logical Operator Or (e.g. the expression 'A Or B' returns True if EITHER A OR B is true and returns False otherwise) 
Not  Negates an evaluation (e.g. the expression 'Not A' returns True if A is false and returns False if A is true) 
It should be noted that the above tables are not an exhaustive list of VBA operators. A more complete list can be obtained from the Visual Basic Developer Center Website
VBA also has a large number of builtin functions that are available to be used in your VBA code. Some of the more commonly used VBA functions are listed below.
Function  Action  

Abs  Returns the absolute value of a supplied number.
 
Chr  Returns the character associated with a supplied character code.
 
Date  Returns the current system date.  
DateAdd  Adds a specified time period to a supplied date. The function has the format DateAdd(Interval, Number, Date), where the Interval argument specifies the type of time interval to be added to the supplied date.
 
DateDiff  Calculates the number of specified intervals between now and a supplied date
 
Day  Returns the day of the month for a supplied date
 
Hour  Returns the Hour portion of a supplied time
 
InStr  If supplied with an integer, n, and 2 strings, the InStr function returns the position of the second string within the first string, starting the search from the n'th position in the first string.
 
Int  Returns the integer part of a numeric value.
 
IsDate  Returns True if a supplied value is a date, and False otherwise.
 
IsError  Returns True if a supplied value is an error, and False otherwise.  
IsMissing  If supplied with the name of an optional argument to a function, the IsMissing function returns True if no argument value was passed to the function.  
IsNumeric  Returns True if a supplied value can be evaluated as a number, or False otherwise.  
Left  Returns a specified number of characters from the start of a supplied string. The format of the function is Left(String, Length), where String is the original text string and Length is the number of characters to be returned from the start of the supplied String.
 
Len  Returns the length of a supplied text string.
 
Month  Returns the month number for a supplied date.
 
Mid  Returns a specified number of characters from the middle of a supplied string. The format of the function is Mid(String, Start, Length), where String is the original text string, Start is the start position of the section of String that is to be returned and Length is the length of the returned string.
 
Minute  Returns the Minute portion of a supplied time.
 
Now  Returns the current system date and time.  
Right  Returns a specified number of characters from the end of a supplied string. The format of the function is Right(String, Length), where String is the original text string and Length is the number of characters to be returned from the end of the supplied String.
 
Second  Returns the Second portion of a supplied time.
 
Sqr  If supplied with numeric value, the Sqr function returns the square root of that value.
 
Time  Returns the current system time.  
UBound  Returns the upper subscript of a supplied array.  
Year  Returns the year of a supplied date.

Note that the above list only provides a selection of the more commonly used Excel Visual Basic builtin functions. A more comprehensive list of the builtin VBA functions is provided on the VBA Functions page or on the Tech on the Net website.