Points in the coordinate plane can give us information about a situation. One common situation is about money.

For example, to open a bank account, money has to be added to the account. The account balance is the amount of money in the account at any given time. If we put in $350 when opening the account, then the account balance will be 350.

Sometimes we may have no money in the account and need to borrow money from the bank. In that situation, the account balance would have a negative value. If we borrow $200, then the account balance is -200.

A coordinate plane can be used to display both the balance and the day or time. This allows us to see how the balance changes over time or to compare the balances of different days. Similarly, if we plot data such as temperature over time in the coordinate plane, we can see how temperature changes over time or compare temperatures at different times.