Question

ncert class 8 maths chapter all formulas

Answer 1

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).
17. Number Formation
19. A two-digit number ‘ab’ can be written in the form: ab = 10a + b
20. A three-digit number ‘abc’ can be written as: abc = 100a+10b+c
21. A four-digit number ‘abcd’ can be formed: abcd = 1000a+100b+10c+d