I need Positive and Negative values working together

A1= 13.44
B1= 2.68
=A1*20%, gives you the result for B1

But what if i want to stay with a 20% +/- margin if A2 was a negative? EX:
A2= -13.44
B2= -2.68, I need this number to be higher then the A2 result

I need a formula that can have, +/-, both work together

How can 20% be higher? Do you mean that b2= +2.68

=ABS(A2* 0.2)