The ABS function has one parameter:
Allowed Inputs: field value or a number
The only parameter of the ABS function is the value that the function should generate the absolute value for. Either use the query builder or the type a value option to enter a number.
The output of the ABS function is the absolute value of the number provided.
For example ABS(1000) would result in 1000 and ABS(-1000) would result in 1000.