Maths formulas for class 8 include the formulas from all the chapters in NCERT class 8 Maths book. Here you will find all the formulas in a PDF file, including Rational Number, Algebraic Expressions, Exponents and Powers, Mensuration, and other chapters.

These formulas for class 8 are beneficial while preparing for your exam. You can get the printout or read the formulas online. Please note that you need to practice more and more to memorize all the maths formulas. You can also review the essential maths formulas for upcoming classes (i.e., Class 9 and Class 10). We have prepared this formula PDF sheet based on the NCERT & CBSE syllabus. We will soon update Hindi medium study materials.

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## Rational Numbers Maths Formulas for Class 8

In class 8, you will learn about another type of number. i.e., Rational Numbers. In this section, we have provided maths formulas for class 8 to study rational numbers. You will also find essential properties of rational numbers and other numbers.

If r = p/q, then r is a rational number.

Where p and q are integers and qā 0.

### Properties of Numbers

#### Closure

Number Type | Operation | Condition | Conclusion |

Addition | for two whole numbers a and b, a+b is also a whole number. | Whole numbers are closed under addition | |

Whole Numbers | Subtraction | a-b is not always a whole number (e.g., 4-6 = -2) | Whole number are not closed under subtraction |

Multiplication | 3×5 = 15, a whole number | Whole numbers are closed under multiplication | |

Division | 4Ć·6 = 2Ć·3, not a whole number | Whole numbers are not closed under division | |

Addition | for two integers a and b, a+b is also an integer | Closed under addition | |

Integers | Subtraction | 4-6 = -2, an integer | Closed under subtraction |

Multiplication | -3×5 = -15, an integer | Closed under multiplication | |

Division | 4Ć·6 = 2Ć·3, not a whole number | Not closed under division | |

Addition | (1/2) + (2/3) = 7/6, a rational number | Rational numbers are closed under addition | |

Rational Numbers | Subtraction | (5/2) ā (1/2) = 2, a rational number | Closed under subtraction |

Multiplication | (3/2) x (1/5) = 3/10, a rational number | Closed under multiplication | |

Division | (2/5) Ć· 0, not defined | Rational numbers are not closed under division |

#### Commutativity

Number Type | Operation | Condition | Conclusion |

Addition | a + b = b + a | Addition is commutative | |

Whole Numbers | Subtraction | a ā b ā b ā a | Subtraction is not commutative |

Multiplication | a x b = b x a | Multiplication is commutative | |

Division | a Ć· b ā b Ć· a | Division is not commutative | |

Addition | a + b = b + a | Addition is commutative | |

Integers | Subtraction | a ā b ā b ā a | Subtraction is not commutative |

Multiplication | a x b = b x a | Multiplication is commutative | |

Division | a Ć· b ā b Ć· a | Division is not commutative | |

Adition | (-3/8) + (1/9) = 1/9 + (-3/8) | Addition is commutative for rational numbers | |

Rational Numbers | Subtraction | (1/2) ā (2/5) ā (2/5) ā (1/2) | Subtraction is not commutative for rational numbers |

Multiplication | (2/5) x (3/8) = (3/8) x (2/5) | Multiplication is commutative for rational numbers | |

Division | (2/5) Ć· (4/7) ā (4/7) Ć· (2/5) | Division is not commutative for rational numbers. |

#### Associativity for Whole Numbers & Integers

Operation | Condition | Conclusion |

Addition | (a + b) + c = a + (b + c) | Associative |

Subtraction | (a ā b) ā c ā a ā (b ā c) | Not Associative |

Multiplication | (a x b) x c = a x (b x c) | Associative |

Division | (a Ć· b) Ć· c ā a Ć· (b Ć· c) | Not Associative |