++ is an operator that increments the operand. The value of the operand in the expression is incremented first if the ++ is before the operand. The value of the operand in the expression is the same value if the ++ is after the operand.

Simply defining, in an expression like A+B

A is an Operand

B is an Operand

Plus is the Operator in between

Subtract with borrow.Subtracts source operand and borrow flag from destination operand.

Yes, both operand 1 and operand 2 can be in memory in the 8086. An example is the string copy primative, which takes source and destination operands to be memory pointed to by DS and ES.

No, a unary expression consists of one operand and one operator