The number system is a fundamental concept in mathematics and plays a crucial role in quantitative aptitude. It involves understanding the different types of numbers, their properties, and operations. This knowledge is essential for solving various problems, including those encountered in competitive exams like CAT.


There are several types of numbers in the number system, including:

- Natural Numbers: These are the counting numbers starting from 1 and going up to infinity.

- Whole Numbers: This includes all the natural numbers along with zero (0).

- Integers: Integers include all whole numbers and their negatives.

- Rational Numbers: Rational numbers are those that can be expressed as a fraction, where the numerator and denominator are integers.

- Irrational Numbers: Irrational numbers cannot be expressed as a fraction and have non-terminating, non-repeating decimal representations.

- Real Numbers: Real numbers include both rational and irrational numbers, covering the entire number line.


In the number system, various operations can be performed on numbers, including:

- Addition: Combining two or more numbers to get a sum.

- Subtraction: Finding the difference between two numbers.

- Multiplication: A process of repeated addition, where the result is the product of the numbers.

- Division: Splitting a number into equal parts or finding the quotient of two numbers.

- Exponents: Raising a number to a power, indicating repeated multiplication.

- Roots: Finding the number that, when multiplied by itself a certain number of times, gives the original number.


The number system is extensively used in quantitative aptitude, which is a crucial section in exams like CAT. Some common applications include:

- Percentage: Understanding percentages involves the concept of fractions and decimals, which are part of the number system.

- Ratio and Proportion: Ratio and proportion problems often require manipulating numbers using the operations in the number system.

- Profit and Loss: Calculating profits and losses involves working with numbers and performing operations such as addition, subtraction, multiplication, and division.

- Time and Work: Problems related to time and work require understanding fractions, decimals, and the relationship between different quantities.

- Speed, Time, and Distance: Solving problems related to speed, time, and distance often involves performing calculations using the number system.

In conclusion, a strong understanding of the number system is essential for success in quantitative aptitude, particularly in exams like CAT. By grasping the different types of numbers and their properties, as well as mastering the various operations, you will be well-equipped to tackle a wide range of problems.