3.3 Integers
People are sometimes confused by negative numbers when they first encounter them. How can I have a negative amount of anything? I can’t physically have fewer than no apples, can I?
To get around this, we introduce the idea that a positive number of things or amount of money means something you have. A negative number or amount means what you owe someone else.
If you have $100 and you write a check or pay a bill electronically for $120, one of two things will likely happen. The first option is for the payment to fail, and your bank may charge you a fee. The second is that the bank will pay the full amount, let you know you are overdrawn, and charge you a fee. You will then need to pay the overdrawn amount quickly or have it paid from some other account.
You started with $100 and ended up with $–20 before repayment. You owe the bank $20. If you deposit $200 in your account immediately, your balance will be $180, which is $–...
