Mathematics is an integral part of our universe because it encompasses all aspects of our day-to-day lives. Regardless of how far you attempt to run away from math, it will continuously follow your path.
These numbers do not include fractions, decimals, or negative integers. Often seen as the foundation for many mathematical operations, whole numbers are used in various fields, from finance to science.
In mathematics, function refers to the relation between sets of elements and the identity function is a form of continuous function. For overall knowledge of its properties, you must study the different aspects of it.