# Maths Formulas for Class 8

Maths Formulas for Class 8 provided on this page covers all the major formulas that you might need during your Class 8. Students can solve the Maths Problems in an effective way by applying the 8th Class Maths Formulae. You will no longer feel the concepts of Maths difficult to grasp with our Class 8th Maths Formulae Sheet & Tables. Get acquainted with the concepts better by practicing Maths Formulas on a day to day basis.

## Class 8 Maths Formulae Sheet & Tables

You will find common and most important CBSE Class 8th Maths Formulas in the coming sections. Recall them and implement them in your problems to get the Solutions instantly. Memorizing the 8th Standard Mathematics Formulas will not be difficult once you solve a sufficient number of problems. Get a good grip on the concepts of Class 8 and keep all the Math Formulae at your fingertips.

• Mensuration Class 8 Formulas
• Linear Equations in One Variable Class 8 Formulas
• Factorisation Class 8 Formulas
• Exponents and Powers Class 8 Formulas
• Direct and Inverse Proportions Class 8 Formulas
• Cubes and Cube Roots Class 8 Formulas
• Comparing Quantities Class 8 Formulas
• Algebraic Expressions and Identities Class 8 Formulas
• Introduction To Graphs Class 8 Formulas
• Visualising Solid Shapes Class 8 Formulas
• Squares and Square Roots Class 8 Formulas
• Data Handling Class 8 Formulas
• Understanding Quadrilaterals Class 8 Formulas
• Rational Numbers Class 8 Formulas
• Practical Geometry Class 8 Formulas
• Playing with Numbers Class 8 Formulas

### 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/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.

### 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.

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