use sum function with negative variable in sas

Question

I'm new to sas and not able to figure what this statement does in the data step

sum(column1, -(col2 * col3))

Answer 1

The SUM function returns the sum of the non-missing argument values.

Adding a negative summand expression to column1 is the same as subtracting the expression from column1 . The expression (col2*col3) itself could be missing, negative, 0, or positive.

The maths analog would be

result = column1 + -(col2*col3), being the same as
result = column1 - col2*col3