all maths formulas of class 8
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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:
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
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Algebra Formulas For Class 8
Maths Formulas For Class 8: Laws of Exponents
a0 = 1
a-m = 1/am
(am)n = amn
am / an = am-n
am x bm = (ab)m
am / bm = (a/b)m
(a/b)-m =(b/a)m
(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.
(a + b)2 = a2 + 2ab + b2
(a – b)2 = a2 – 2ab + b2
(a + b) (a – b) = a2 – b2
(x + a) (x + b) = x2 + (a + b)x + ab
(x + a) (x – b) = x2 + (a – b)x – ab
(x – a) (x + b) = x2 + (b – a)x – ab
(x – a) (x – b) = x2 – (a + b)x + ab
(a + b)3 = a3 + b3 + 3ab(a + b)
(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.
Every square number surely ends with 0, 1, 4, 5 6 and 9 at its units place.
A square mysqladmin 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.
If every number in the prime factorization appears three times, then the number is a perfect cube.
The symbol of the cube mysqladmin is ∛.
Cube and Cube mysqladmin: ∛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(1+R100)t
P = Principal,
r = Rate of Interest, and
t = Time Period
Formula of Amount (Compounded Half Yearly): A=P(1+R200)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.
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