On this page you are going to read complete information about what is called an **Odd Numbers**.

We have shared the information of Even Number on the previous page, must read it.

Let us read and understand the odd number on this page.

## What is an Odd Number

Natural numbers which are not exactly divisible by 2 are called odd number.

**Like :-** 1, 3, 5, 7, 9, 11, ………

The Numbers which end in 1, 3, 5, 7, 9 are called odd numbers.

The average of the first n odd numbers is n.

## Odd Number From 1 to 100

1 | 21 | 41 | 61 | 81 |

3 | 23 | 43 | 63 | 83 |

5 | 25 | 45 | 65 | 85 |

7 | 27 | 47 | 67 | 87 |

9 | 29 | 49 | 69 | 89 |

11 | 31 | 51 | 71 | 91 |

13 | 33 | 53 | 73 | 93 |

15 | 35 | 55 | 75 | 95 |

17 | 37 | 57 | 77 | 97 |

19 | 39 | 59 | 79 | 99 |

## Odd Number Question

Q.1 What is the average of first 9 odd number?

A.5

B.7

C.9

D.3

Solution:- According to the question,

The numbers which are not divisible by 2 are called odd number.

Hence first 7 are odd number.

1, 3, 5, 7, 9, 11, 13, 15, 17

Average of numbers = (sum of given numbers)/(number of given number)

Average of first 9 odd numbers = (1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17)/9

Average of first 9 odd numbers = 81/9

Average of first 9 odd numbers = 9

Q.2 The sum of the first 20 odd number is?

A.381

B.400

C.425

D.625

Solution :- According to the question,

First 20 are odd number.

1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39

The sum of first 20 odd number = (1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 + 23 + 25 + 27 + 29 + 31 + 33 + 35 + 37 + 39)

Sum of first 20 odd numbers = 400

Q.3 What is the sum of first 40 odd number?

A.1200

B.1600

C.2000

D.2400

Solution:- According to the question,

sum of first 40 odd number

1, 3, 5, 9, ……………………… 77, 79

a = 1,

d = 3 – 1

d = 2

n = 80

Sum ⇒ Sn = n/2 [2a + (n – 2)d]

Sn = 40/2 [2×1 + (40 – 1) × 2]

Sn = 20 (2 + 39 × 2)

Sn = 20 (2 + 78)

Sn = 20 × 80

Sn = 1600

Q.4 The sum of three consecutive odd numbers is 153. is the smallest number among them.

A.49

B.47

C.43

D.41

Suppose that

Three consecutive odd numbers are x, x+2, and x+4 respectively.

According to Question,

x + x+2 + x+4 = 153

3x + 6 = 153

3x = 153 – 6

3x = 147

x = 147/3

x = 49

Q.5 The sum of 6 consecutive odd numbers is 38 more than twice the largest number. Find the sum of these six number?

A.42

B.50

C.72

D.60

Let the 6 consecutive odd number be x, x + 2, x + 4, x + 6, x + 8, and x + 10 respectively.

x + x + 2 + x + 4 + x + 6 + x + 8 + x + 10 – 2(x + 10) = 38

4x + 10 = 38

4x = 38 – 10

4x = 28

x = 7

Required sum = 6x + 30

Required sum = 6 × 7 + 30

Required sum = 42 + 30

Required total = 72

### FAQ

**Q.1 What are odd numbers?**

**Ans. **Odd numbers are **the numbers that cannot be divided by 2 evenly**.

**Q.2 What are odd numbers 1 to 100?**

**Ans.** Below is a list of all odd numbers from 1 to 100 : 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, 37, 39, 41, 43, 45, 47, 49, 51, 53, 55, 57, 59, 61, 63, 65, 67, 69, 71, 73, 75, 77, 79, 81, 83, 85, 87, 89, 91, 93, 95, 97, 99.

**Q.3 Is 2 is a odd number?**

**Ans.** **Odd number are those number that cannot be divided into two equal parts**.

**Q.4 Which is odd and even number?**

**Ans.** Even numbers are divisible by 2 without remainders. They end in 0, 2, 4, 6, or 8. Odd number are not evenly divisible by 2 and end in 1, 3, 5, 7, or 9.

**Q.5 Which one is always odd?**

**Ans.** Odd number always have **1, 3, 5, 7, or 9** in their units place. Even numbers always have 0, 2, 4, 6, or 8 in their units place.

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