The number -4 is a negative integer, which means it is less than zero. In mathematics, negative numbers are used to represent values that fall below a defined point, such as temperatures below freezing or debts in financial contexts. Negative numbers, including -4, are often used in various calculations, such as subtraction and temperature changes. For example, if the temperature drops from 2 degrees to -4 degrees, it has decreased by 6 degrees. Understanding negative numbers is essential in fields like mathematics, science, and finance.