As TK told you Andrea, two minuses make a plus,
so 2.54 - (-1.81) = 2.54 + 1.81 = 4.35.
Here's a way to look at this:
+ 4.35
- 1.81
=====
+ 2.54
Now, 2.54 - (-1.81) means:
1.81 was deducted from a number, to leave 2.54.
Now, what was that number before the 1.81 was minused off?
In other words, - (-1.81) means: "minus off", or cancel the -1.81 deduction;
so to cancel it off, you have to ADD it back on...
Sure hope I haven't confused you further :shock: