ACCESS will not convert your text-formatted numbers to a number in order to
use the "+" operator. For text strings, + also concatenates the two strings.
It differs from & operator in that & does not proprogate Null values through
the operation, while + does.
For example:
Null & "Ken" produces "Ken"
Null + "Ken" produces Null
To add numbers that are text-formatted, use the Val function to convert them
to numbers:
Val([Field1]) + Val([Field2])
Alternatively, you also can use other functions (CInt for integer
conversion, CLng for long integer conversion, CSng for single conversion,
CDbl for double conversion, CCur for currency conversion, etc.).