Prime Numbers: 1 TO 100
PRIME NUMBERS FROM 1 TO 100
What are prime numbers? They are numbers that have only two factors which are the number itself and 1. There are 25 numbers between 1 to 100, that are prime. The positive whole numbers that are not prime are called composite numbers.
The difference between prime and non-prime (composite) numbers is:
| PRIME NUMBERS | COMPOSITE NUMBERS |
| Prime numbers have only two factors which are the number itself and 1 | Composite numbers have 3 or more than 3 factors |
| The smallest prime number is 2 | The smallest composite number is 4 |
| They cannot be divided by any other number except 1 or the number itself | Composite numbers can be divided by many numbers and have many multiples |
| Example: 2, 3, 5, 7, 11, 13 and so on | Example: 4, 6, 8, 9, 10, 12 and so on |
The 25 prime numbers from 1 to 100 are:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97.
PROPERTIES OF A PRIME NUMBER
Prime numbers have the following properties:
- They have only two factors.
- They are whole numbers greater than 0
- All prime numbers except 2 are odd.
- Prime factorization method is used to find prime numbers.
- Prime numbers cannot be divided without a remainder by any other number other than 1 or the number itself.
HOW DO WE FIND PRIME NUMBERS 1 TO 100?
See the following box with counting from 1 to 100
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
| 31 | 32 | 33 | 34 | 35 | 36 | 37 | 38 | 39 | 40 |
| 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 |
| 51 | 52 | 53 | 54 | 55 | 56 | 57 | 58 | 59 | 60 |
| 61 | 62 | 63 | 64 | 65 | 66 | 67 | 68 | 69 | 70 |
| 71 | 72 | 73 | 74 | 75 | 76 | 77 | 78 | 79 | 80 |
| 81 | 82 | 83 | 84 | 85 | 86 | 87 | 88 | 89 | 90 |
| 91 | 92 | 93 | 94 | 95 | 96 | 97 | 98 | 99 | 100 |
- We are keeping the number 1 because it is neither a prime nor a composite number.
- Since 2 is a prime number, highlight it (done with yellow here) and highlight all the even numbers which are multiples of 2 with another colour (done with blue here to show they are composite numbers).
- Highlight 3 as a prime number but all its multiples with the colour used for composite numbers (blue here).
- Now, highlight 5 as a prime number and all the multiples of 5 which are numbers ending in 0 and 5 as composite numbers.
- Lastly, highlight 7 as a prime number and all the multiple of 7 till 100 with the colour used for composite numbers.
The remaining numbers are all prime numbers and can be highlighted as such.
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Frequently Asked Questions
1. Is 23 a prime number?
Ans: Yes. 23 is a prime number with only two factors 1 and 23.
2. Is 65 a prime number?
Ans: No. 65 has many factors which are 1, 5, 13, 65 so it is a composite number.
3. Which is the least possible prime number?
Ans: The smallest prime number is 2. It is also the only number that is prime and even. All other even numbers are multiple of 2 and all other possible prime numbers are odd numbers.