Question

where do you get minus numbers ? there are only plus numbers only minus operations ! have you ever seen a minus dollar bill ? yet you see them in math problems all the time.

Answer 1

Think of minus numbers as numbers you're subtracting.

Answer 2

that what creates confusion, thinking of positive numbers as 'negative' numbers.

Answer 3

ok first of all, i didn't say anything about thinking positive numbers as negative numbers, but here are some real life applications..
1. Stock market, so investors can choose carefully
2. Statistics, a president's approval numbers will be in negative as economy worsens.
and there are a lot more :P