Hi I am working from a book and I'm having a problem.

The text below is an example from the book. When I enter this sum into my calculator exactly as shown below it says -1 not 1

What am I doing wrong? Is this an error in the book?For example, 3+(−4) means that (−4) is being added to 3; this is equivalent to subtracting 4 from 3, with the result (1).