Index form, also known as exponential form or scientific notation, is a way of writing very large or very small numbers using exponents or powers. In index form, a number is written as a base raised to a power or exponent. The base is usually a number between 1 and 10, and the exponent is an integer that indicates how many times the base is multiplied by itself. For example, the number 10,000 can be written in index form as 10^4, where 10 is the base and 4 is the exponent. Index form is commonly used in scientific and mathematical calculations, as it makes it easier to work with very large or very small numbers. There are online calculators available that can convert numbers to index form.