
Subtraction
Result = expression1  expression2
For each cell, the value of expression2 is subtracted from the value of expression1. This difference is assigned to the corresponding cell on Result.
A cell with missing value on expression1 or expression2 or on both expressions is assigned a missing value on Result.
Result=expression1 is an alternative notation for Result = Result  expression1
This operation belongs to the group of Arithmetic operators
Result.map  Expr1.map  Expr2.map 