Product number (P/N): + (Key),
Keywords/Tags: + (Key)
Classification: / Key,
Info: WIKIPEDIA:
The plus sign is a binary operator that indicates addition, as in 2 + 3 = 5
It can also serve as a unary operator that leaves its operand unchanged (+x means the same as x)
This notation may be used when it is desired to emphasize the positiveness of a number, especially in contrast with the negative numbers (+5 versus -5).
The plus sign can also indicate many other operations, depending on the mathematical system under consideration.
Internet: Link-1: WIKIPEDIA