CBSE Class 9 Maths Number Systems Formulas

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Class 9 Maths Number System Formulas

Do you find it difficult to cope up with the Math formulas and equations? Do math formulas seem to be complicated to remember? Not a matter to distress over. What if we tell you that you no longer require struggling to mug up all Math formulas of Class 9? Yes! You will get formulas of number system class 9 in the Class 9 Maths Formula Sheets designed by subject matter experts at Vedantu. This sheet is inclusive of all formulas of number system class 9 chapters wise.

Formulas of Maths of Class 9

CBSE Class 9 Maths Formulas all chapters are available for free access and revision on You can simply download the important Maths Formulas and equations PDF 9th class to solve the problems easily, quickly and score higher grades in your Class 9 CBSE Board Exams at Vedantu.

Number System Formula Class 9

Natural Numbers: These are in numerical form of -1, 2, 3, 4, 5, 6, 7, 8, 9, 10..........denoted by N.

Whole Numbers: These are in numerical form of – 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10..........denoted by W.

Integers: -9, -8, -7, -6, -5, -4, -3, -2, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 denoted by Z.

Rational Numbers: All the numbers that can be mathematical written in the form p/q, q ≠0 are known as rational numbers where p and q refers to the integers.

Irrational Numbers: A number‘s’ is known as irrational, if it cannot be mathematically written in the form p/q where p and q are integers and q ≠ 0.

Decimal Expansion: Such an algebraic expansion in the decimal form of a rational number is either terminating or non terminating recurring. Therefore, we can say that a number whose decimal expansion is either terminating or non terminating recurring is what we call a rational number. There are following properties of a decimal expansion which are as below:

  • For an irrational number, the decimal expansion is non terminating and non recurring.

  • All the rational numbers and irrational numbers can be taken together.

  • We can make a collection of real numbers.

  • A real number may be either rational or irrational.

  • If ‘r’ is rational and ‘s’ is irrational then r + s, r - s, r . s will invariably be the irrational numbers, however r/s may either be rational or irrational

  • We can represent every irrational number on a number lines using Pythagoras theorem.

  • Rationalization is the method of taking out square roots from the denominator. For example, for a mathematical expression 2 + √6/√4, to remove we will multiply both numerator as well as denominator by √4.

Important Number System Formula Class 9

1. Polynomial Expressions Formulas


(2x + 3y),(3x − 2y)etc


3, 2x, 23y etc.


x2 + 4x + 5 etc.

Linear polynomial

x+2, 3x + 5 etc

Quadratic polynomial

ax2 + bx + c etc

BiQuadratic polynomial

x4 + 5x3 + 2x2 + 3

Cubic polynomial

x3 + 4x2 + 5 etc

2. Coordinate Geometry Formulas

Equation of a line

ax + by + c = 0

Equation of a circle

x² +y² =r²

Here ‘r’ refers to the radius of the circle

Equation of an ellipse


Equation of a parabola

y² = 4ax

Equation of a hyperparabola

x²/a² - y²/b²=1

Angle between two lines

θ = tan²−1(m/1+m1m2)

Distance formula

√[(x2−x1)²+ (y2−y1)²]

3. Circles Formulas

Area of circle 


Diameter of circle 


Circumference of circle


Sector angle of circle

θ = (360/(πr)

Area of the sector


Area of the circular ring

π × (R²−r²)

r = Radius of inner circle.

R = Radius of outer circle.

θ = Angle between two radii.

FAQ (Frequently Asked Questions)

Q1. How can I Learn all Formulas of Number System Class 9?

Answer: The best way to learn all number system class 9 formulas is to have them handy. You should have access to categorical formula sheets whenever, wherever so that you are able to keep practicing them and quickly correct or retain them if not able to remember. It gets difficult to learn formulas when you try to grasp them from scattered chapters and equations. The key is to have them in place in an ordered manner like one above.

Q2. How can I Find all Formulas of Number System Class 9?

Answer: The team of Math experts at Vedantu has created a list of number system formulas class 9 Mathematics formulas with logical explanations. In addition to formulas and equations, you will also find methods of solving as well as how and where to use them. The comprehensive formula sheet is available at Vedantu for free PDF download and you can have access to it anytime.

Q3. What is the Benefit of Formula Sheet of Number System Class 9?

Answer: Success is said to be the sum of little attempts that are repeated daily and frequently. Using this sheet of important formulas as a curriculum of your exam preparations, you will be able to understand the logic, appropriate method of solving, solving complex numerical problems faster, score higher marks in school exams and crack several competitive exams!