Quantity refers to the amount or number of something that can be measured or counted.
In mathematics, quantity represents a value that may be expressed as a numerical value.
The term "quantity" is commonly used in:
1. Physics - to describe measurable properties like mass, length, time
2. Economics - referring to the amount of goods or services
3. Everyday language - to indicate how much or how many of something
4. Chemistry - to specify amounts of substances