The most common use is to represent a loss of something, usually money. So if you make up a cash flow statement, debits are negative. In a balance sheet, liabilities and debts would be negative.
In electrical engineering, negative voltages are used on circuit diagrams
Temperatures colder than 0 deg are written as negative numbers
The stock market uses negative numbers when indicating downward swings and trends
Answers & Comments
The most common use is to represent a loss of something, usually money. So if you make up a cash flow statement, debits are negative. In a balance sheet, liabilities and debts would be negative.
In electrical engineering, negative voltages are used on circuit diagrams
Temperatures colder than 0 deg are written as negative numbers
The stock market uses negative numbers when indicating downward swings and trends