Use the subtraction (-) and division (/) operators, and the ABS function to do this task.
The formula =(B2-A2)/ABS(A2) will produce .25; format it to a percent and you're done.
The ABS function returns the absolute value of a number. The absolute value of a number is the number without its sign.
Syntax: ABS(number) Number is the real number of which you want the absolute value.
For example, the absolute value of -5 is 5.