Maths Formulas For Class 8: Important Chapterwise Formulas For Class 8 Maths

Maths Formulas For Class 8: For a Class 8 student, it becomes difficult to understand the rise in difficulty level from his previous classes. Also, for a subject like Mathematics, you got to be attentive all the times. The subject holds a lot of importance in both your education as well as your personal life. For a good level of understanding, you need to conquer your Maths Formulas for Class 8 first and then move on to implement them to solve your questions.

One may wonder where to find the exact Maths formulas for Class 8 for a specific set of problems. This is the reason why we are bringing this article right in front of you. We will be providing you with all Maths formulas for Class 8 under one page so that you don’t face any problem.

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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.

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

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Let’s take a look at some of the important chapter-wise list of Maths formulas for Class 8.

Maths Class 8 Formulas: Rational Numbers

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

1. Additive Identity: (a ⁄ b + 0) = (a ⁄ b)
2. Multiplicative Identity: (a ⁄ b) × 1 = (a/b)
3. Multiplicative Inverse: (a ⁄ b) × (b/a) = 1
4. Closure Property – Addition: For any two rational numbers a and b, a + b is also a rational number.
5. Closure Property – Subtraction: For any two rational numbers a and b, a – b is also a rational number.
6. Closure Property – Multiplication: For any two rational numbers a and b, a × b is also a rational number.
7. Closure Property – Division: Rational numbers are not closed under division.
8. Commutative Property – Addition: For any rational numbers a and b, a + b = b + a.
9. Commutative Property – Subtraction: For any rational numbers a and b, a – b ≠ b – a.
10. Commutative Property – Multiplication: For any rational numbers a and b, (a x b) = (b x a).
11. Commutative Property – Division: For any rational numbers a and b, (a/b) ≠ (b/a).
12. Associative Property – Addition: For any rational numbers a, b, and c, (a + b) + c = a + (b + c).
13. Associative Property – Subtraction: For any rational numbers a, b, and c, (a – b) – c ≠ a – (b – c)
14. Associative Property – Multiplication: For any rational number a, b, and c, (a x b) x c = a x (b x c).
15. Associative Property – Division: For any rational numbers a, b, and c, (a / b) / c ≠ a / (b / c) .
16. Distributive Property: For any three rational numbers a, b and c, a × ( b + c ) = (a × b) +( a × c).

Number Formation

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

Maths Formulas For Class 8: Laws of Exponents

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

Maths Formulas For Class 8: Algebraic Identity

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

• a) 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.
• b) 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)

Maths Formulas For Class 8 Square & Square Roots

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

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

Maths Formulas For Class 8 Cube & Cube Roots

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

1. If every number in the prime factorization appears three times, then the number is a perfect cube.
2. The symbol of the cube root is ∛.
3. Cube and Cube root: ∛27 = 3 and 3³ = 27.

Maths Formulas For Class 8 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

Maths Formulas For Class 8 Data Handling & Probability

Any useful information that can be utilized 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.

1. A class interval is the specific range of numbers such as 10-20, 20-30, 30-40, and so forth.
2. For a Class Interval of 10-20, Lower Class Limit = 10 and Upper-Class Limit = 20
3. Frequency is the number of times a particular value occurs.

Probability = Number of Favourable Outcomes / Total Number of Outcomes

Maths Formulas For Class 8 Geometry

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

• 1. LSA – Lateral/Curved Surface Area
• 2. TSA – Total Surface Area

Name of the Solid Figure	Formulas
Cuboid	LSA: 2h(l + b) TSA: 2(lb + bh + hl) Volume: l × b × h l = length, b = breadth, h = height
Cube	LSA: 4a2 TSA: 6a2 Volume: a3 a = sides of a cube
Right Pyramid	LSA: 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 Cylinder	LSA: 2(π × r × h) TSA: 2πr (r + h) Volume: π × r2 × h r = radius, h = height
Right Circular Cone	LSA: πrl TSA: π × r × (r + l) Volume: ⅓ × (πr2h) r = radius, l = slant height, h = height
Right Prism	LSA: p × h TSA: LSA × 2B Volume: B × h p = perimeter of the base, B = area of base, h = height
Sphere	LSA: 4 × π × r2 TSA: 4 × π × r2 Volume: 4/3 × (πr3) r = radius
Hemisphere	LSA: 2 × π × r2 TSA: 3 × π × r2 Volume: ⅔ × (πr3) r = radius

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Maths Formulas For Class 8: Important FAQs

Here are some important frequently asked questions related to Class 8 Maths formulas.

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These are some of the important maths formulas for Class 8. These will prove to be helpful in making your journey a rather easy one. Solve the free Class 8 Maths Questions and refer to these formulas when necessary. With passing time, you will improve.

If you have any queries, feel free to comment them down and we will get back to you. Embibe wishes you all the best!

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