CBSE Class 8 Maths Formulas: Check chapter-wise formulas - Embibe
  • Written By Akash_Anand
  • Last Modified 17-07-2022
  • Written By Akash_Anand
  • Last Modified 17-07-2022

CBSE Class 8 Maths Formulas

CBSE Class 8 Maths Formulas: In order to prepare for the board exams, CBSE Class 8 Maths formulas are a good starting point. Therefore, it is important to know and learn them thoroughly. It makes sense that children experience anxiety because learning arithmetic concepts can be challenging. To get a high level of knowledge, students must first learn 8th Class Maths formulas and then move towards solving questions.

To make things easier for students, this article provides an overview of all the arithmetic formulas for the eighth grade. This will enable students to go past their learning barrier and maintain composure throughout the exam. The important Class 8 Maths formulas discussed in this article will not only make it easier for students to understand their significance, but they will also become familiar with several useful learning strategies that can be quickly incorporated into their studies.

NCERT Maths Formulas for Class 8

Many students argue about the fact that Maths formulas are hard to grasp. However, if you understand the meaning of the formulas, practice them regularly, and solve a sufficient number of questions, all the formulas will be at your fingertips. Students will not need the Maths formulas for Class 8 CBSE PDF now as we have listed down all the formulas for you.

CBSE Class 8 Maths has the following chapters:

  • Chapter-1: Rational Numbers
  • Chapter-2: Linear Equation in One Variable
  • Chapter-3: Understanding Quadrilaterals
  • Chapter-4: Practical Geometry
  • Chapter-5: Data Handling
  • Chapter-6: Square and Square Roots
  • Chapter-7: Cube and Cube Roots
  • Chapter-8: Comparing Quantities
  • Chapter-9: Algebraic Expressions and Identities
  • Chapter-10: Mensuration
  • Chapter-11: Exponents and Power
  • Chapter-12: Direct and Inverse Proportion
  • Chapter-13: Factorization
  • Chapter-14: Introduction to Graphs
  • Chapter-15: Playing with Numbers

CBSE Class 8 Maths Formulas: Rational Numbers

Any number that can be written in the form of p ⁄ q where q ≠ 0 are rational numbers. It possesses the properties of:

  • Additive Identity: (a ⁄ b + 0) = (a ⁄ b)
  • Multiplicative Identity: (a ⁄ b) × 1 = (a/b)
  • Multiplicative Inverse: (a ⁄ b) × (b/a) = 1
  • Closure Property – Addition: For any two rational numbers a and b, a + b is also a rational number.
  • Closure Property – Subtraction: For any two rational numbers a and b, a – b is also a rational number.
  • Closure Property – Multiplication: For any two rational numbers a and b, a × b is also a rational number.
  • Closure Property – Division: Rational numbers are not closed under division.
  • Commutative Property – Addition: For any rational numbers a and b, a + b = b + a.
  • Commutative Property – Subtraction: For any rational numbers a and b, a – b ≠ b – a.
  • Commutative Property – Multiplication: For any rational numbers a and b, (a x b) = (b x a).
  • Commutative Property – Division: For any rational numbers a and b, (a/b) ≠ (b/a).
  • Associative Property – Addition: For any rational numbers a, b, and c, (a + b) + c = a + (b + c).
  • Associative Property – Subtraction: For any rational numbers a, b, and c, (a – b) – c ≠ a – (b – c)
  • Associative Property – Multiplication: For any rational number a, b, and c, (a x b) x c = a x (b x c).
  • Associative Property – Division: For any rational numbers a, b, and c, (a / b) / c ≠ a / (b / c) .
  • Distributive Property: For any three rational numbers a, b and c, a × ( b + c ) = (a × b) +( a × c).

Number Formation

  • A two-digit number ‘ab’ can be written in the form: ab = 10a + b
  • A three-digit number ‘abc’ can be written as: abc = 100a+10b+c
  • A four-digit number ‘abcd’ can be formed: abcd = 1000a+100b+10c+d

CBSE Class 8 Maths Formulas: Laws of Exponents

  1. a0 = 1
  2. a-m = 1/am
  3. (am)n = amn
  4. am / an = am-n
  5. am x bm = (ab)m
  6. am / bm = (a/b)m
  7. (a/b)-m =(b/a)m
  8. (1)n = 1 for infinite values of n.

 

CBSE Class 8 Maths Formulas: Algebraic Identity

Algebraic Identities comprise several equality equations which consist of different variables.

  • Linear Equations in One Variable: A linear equation in one variable has the maximum one variable of order 1. It is depicted in the form of ax + b = 0, where x is the variable.
  • Linear Equations in Two Variables: A linear equation in two variables has the maximum of two variables of order 2. It is depicted in the form of ax2 + bx + c = 0.

  1. (a + b)2 = a2 + 2ab + b2
  2. (a – b)2 = a2 – 2ab + b2
  3. (a + b) (a – b) = a2 – b2
  4. (x + a) (x + b) = x2 + (a + b)x + ab
  5. (x + a) (x – b) = x2 + (a – b)x – ab
  6. (x – a) (x + b) = x2 + (b – a)x – ab
  7. (x – a) (x – b) = x2 – (a + b)x + ab
  8. (a + b)3 = a3 + b3 + 3ab(a + b)
  9. (a – b)3 = a3 – b3 – 3ab(a – b)

 

CBSE Class 8 Maths Formulas: Square and Square Roots

If a natural number, m = n2 and n is a natural number, then m is said to be a square number.

  • Every square number surely ends with 0, 1, 4, 5, 6, and 9 at its units place.
  • A square is the inverse operation of the square.

CBSE Class 8 Maths Formulas: Cube and Cube Roots

Numbers, when obtained while multiplied by itself three times, is known as cube numbers.

  • If every number in the prime factorisation appears three times, then the number is a perfect cube.
  • The symbol of the cube is ∛.
  • Cube and Cube mysqladmin: ∛27 = 3 and 33 = 27.

CBSE Class 8 Maths Formulas: Comparing Quantities

Discounts are the reduction value prevailed on the Marked Price (MP).

  • Discount = Marked Price – Sale Price
  • Discount = Discount % of the Marked Price

Overhead expenses are the additional expenses made after purchasing an item. These are included in the Cost Price (CP) of that particular item.

  • CP = Buying Price + Overhead Expenses

GST (Goods and Service Tax) is calculated on the supply of the goods.

  • Tax = Tax % of the Bill Amount

Compound Interest (CI) is the interest which is compounded on the basis of the previous year’s amount.

Formula of Amount (Compounded Annually): \(A = P \left (1 + \frac{R}{100} \right )^t\)

P = Principal,
r = Rate of Interest, and
t = Time Period

Formula of Amount (Compounded Half Yearly): \(A = P \left (1 + \frac{R}{200} \right )^{2t}\)

R/2 = Half-yearly Rate,
2t = Number of Half-Years

CBSE Class 8 Maths Formulas: Data Handling and Probability

Any useful information that can be utilised for some specific use is known as data. These data can be represented either graphically (pictograph/bar graph/pie charts) or symmetrically (tabular form). Find the important Class 8 Maths formulas for Data Handling and Probability.

  • A class interval is the specific range of numbers such as 10-20, 20-30, 30-40, and so forth.
  • For a class interval of 10-20, lower class limit = 10 and upper class limit = 20
  • Frequency is the number of times a particular value occurs.

Probability = Number of Favourable Outcomes/Total Number of Outcomes

CBSE Class 8 Maths All Formulas: Geometry

Here, we will define the geometrical formulas consistently used in Mathematics Class 8. We will use the following abbreviations for convenience:

  • LSA – Lateral/Curved Surface Area
  • TSA – Total Surface Area
Name of the Solid FigureFormulas
CuboidLSA: 2h(l + b)
TSA: 2(lb + bh + hl)
Volume: l × b × h

l = length,
b = breadth,
h = height
CubeLSA: 4a2
TSA: 6a2
Volume: a3

a = sides of a cube
Right PyramidLSA: ½ × p × l
TSA: LSA + Area of the base
Volume: ⅓ × Area of the base × h

p = perimeter of the base,
l = slant height, h = height
Right Circular CylinderLSA: 2(π × r × h)
TSA: 2πr (r + h)
Volume: π × r2 × h

r = radius,
h = height
Right Circular ConeLSA: πrl
TSA: π × r × (r + l)
Volume: ⅓ × (πr2h)

r = radius,
l = slant height,
h = height
Right PrismLSA: p × h
TSA: LSA × 2B
Volume: B × h

p = perimeter of the base,
B = area of base, h = height
SphereLSA: 4 × π × r2
TSA: 4 × π × r2
Volume: 4/3 × (πr3)

r = radius
HemisphereLSA: 2 × π × r2
TSA: 3 × π × r2
Volume: ⅔ × (πr3)

r = radius

List of Important Class 8 Math Formulas  

Consistent practise is essential for success in math. Students are encouraged to solve as many problems as they can, since this will expose them to a variety of formulas. This is a fantastic technique to recall formulas without having to mumble them down. Here is a summarized list of Class 8 math formulas that can be used.

  1. Additive inverse of rational number: a/b = -b/a
  2. Multiplicative Inverse of a/b = c/d , if a/b × c/d = 1
  3. Distributivity a(b – c) = ab – ac
  4. Probability of the occurrence of an event = Number of outcomes that comprise an event/ Total number of outcomes
  5. Compound Interest formula = Amount – Principal, Amount in case the interest is to be calculated annually = Principal ( 1 + Rate/100)n, where ‘n’ is the time period.
  6. (a – b)2 = a2 – 2ab + b2
  7. (a + b) (a – b) = a2 – b2  
  8. Euler’s Formula: For any polyhedron, Number of faces + Number of vertices – Number of edges = 2
  9. Volume of a Cone = (1 / 3 )πr2h
  10. Volume of a Sphere = (4/3) π r3

FAQs on CBSE Class 8 Maths Formulas

Q.1: How to memorise Class 8 Maths formulas?
Ans:
 Refer to the formula sheet as you solve questions. Eventually, you will memorise them and master their application.

Q.2: Is NCERT enough for the Class 8 Maths exam?
Ans:
 Yes, for Class 8, the NCERT Maths textbook is enough.

Q.3: Which book should I prefer for learning Class 8 Maths formulas?
Ans: We advise you to go for NCERT books if you want to know all the essential Class 8 Maths formulas.

Q.4: Is there any website that offers free Class 8 practice questions?
Ans: Embibe provides free Class 8 practice questions to learn and score well in your examinations.

Q.5: How to best use these CBSE Class 8 Maths formulas?
Ans: These Class 8 Maths formulas will help you when you get stuck in some questions while practising the subject. The formulas and properties will help you in quick revision. This way you can prepare well and score better.

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