Prime Numbers
Those natural numbers which are greater than 1 and having only two factors are called prime numbers. One factor is ‘1’, and the other is ‘number itself’.
Those natural numbers which are greater than 1 and having more than two factors are called composite numbers.
For example:
The number 7 has only two factors 1 and 7, so it is a prime number.
The number 9 has more than two factors. It has three factors 1, 3, and 9. So 9 is not a prime number.
Note: 1 is neither the composite number nor a prime number.
Following are the first ten prime numbers:
2 3 5 7 11 13 17 19 23 29
List of Prime Numbers from 1 to 100
- There are 25 prime numbers between 1 and 100.
- Following table shows the prime numbers from 1 to 100:
| Prime Numbers From 1 to 100 | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| 1 to 10 | 11 to 20 | 21 to 30 | 31 to 40 | 41 to 50 | 51 to 60 | 61 to 70 | 71 to 80 | 81 to 90 | 91 to 100 |
| 2 | 11 | 23 | 31 | 41 | 53 | 61 | 71 | 83 | 97 |
| 3 | 13 | 29 | 37 | 43 | 59 | 67 | 73 | 89 | |
| 5 | 17 | 47 | 79 | ||||||
| 7 | 19 | ||||||||
List of Prime Numbers From 101 to 1000
| Prime Numbers From 101 to 1000 | |
|---|---|
| 101 to 200 | 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, and 199. |
| 201 to 300 | 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, and 293. |
| 301 to 400 | 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, and 397. |
| 401 to 500 | 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, and 499. |
| 501 to 600 | 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, and 599. |
| 601 to 700 | 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, and 691. |
| 701 to 800 | 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, and 797. |
| 801 to 900 | 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, and 887. |
| 901 to 1000 | 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, and 997. |
How to Calculate the Prime number
If we want to check the given number is prime or not, then we have to follow the following steps:
- Firstly, we have to write the factors of the given number.
- Then, we have to count the found factors.
- If there are exactly 2 factors of the number, then the number is prime. Otherwise, it is a composite number.
Solved Questions of Prime Numbers
Example 1: Is the number 8 prime or NOT?
Solution:
The given number is 8.
The factors of 8 are
1, 2, 4, and 8.
Thus the number 8 has 4 factors.
Since the number of factors of 8 is NOT exactly 2, so it is NOT a prime number (so
8 is a composite number).
Answer: 8 is not a prime number.
Example 2: Is the number 29 prime or NOT?
Solution:
The given number is 29.
The factors of 29 are
1 and 29.
Thus the number 29 has exactly 2 factors.
Since the number of factors of 29 is exactly 2, so it is a prime number.
Answer: 29 is a prime number.
Example 3: Which of the following given numbers are prime?
1, 7.3, 17, 18, 23, 25, 71, 4/5, 100, 123.
Solution:
17, 23, 71 are prime numbers.
The factors of these numbers are 1 and the number itself. So, these above numbers are prime.
And, the numbers which are left are not prime numbers.
1: It is not greater than 1
7.3: It is a decimal number
18: Factors of 18 are 1, 2, 3, 6, 9, and 18.
25: Factors of 25 are 1, 5, and 25.
4/5: It is not a whole number
100: Factors of 25 are 1, 2, 4, 5, 10, 25, 50 and 100.
123: Factors of 25 are 1, 3, 41, and 123.