The number 900 is a three-digit integer that comes after 899 and before 901. It is often seen in various contexts, such as in mathematics, where it can represent a quantity, a score, or a measurement. In Roman numerals, 900 is written as CM, which signifies a significant value in ancient counting systems. In everyday life, 900 can be found in many places, like the 900 area code used in some regions for telephone numbers. It can also represent milestones, such as 900 days of an event or 900 calories in a meal. Overall, 900 is a versatile number with various applications.