A prime number is a positive integer which has only two factors i. It implies that the number can be divided only by one and itself. For example — 2, 3, 5, 7, 11…. Prime Numbers Facts. The number 2 is only an even prime number. Other even numbers can be divided by 2. So the even numbers which can be divided by 2 are not a prime number.
Zero and 1 are not a prime number. The numbers o and 1 are neither considered as a prime number nor a composite number. Not a single prime number greater than 5 ends with a 5. Since, any number greater than 5 that ends with 5 can be easily divided by 5. So, it cannot be considered as a prime number. Solved Examples. Solution: Factors of 53 are 1 and If you make a mistake, choose a different button. By signing up, you agree to receive useful information and to our privacy policy.
Shop Math Games. Skip to main content. Search form Search. Solution: 1 yd x 7 yd The whole-number dimensions, 1 and 7, of the rectangular garden above, are the factors of the number 7. Solution: 1 yd x 8 yd, 2 yd x 4 yd The whole-number dimensions, 1, 2, 4 and 8, of the rectangular gardens in Problem 2, are the factors of the number 8.
Definitions A prime number has only two factors: 1 and itself. To determine if a number is prime or composite, follow these steps: Find all factors of the number. If the number has only two factors, 1 and itself, then it is prime. If the number has more than two factors, then it is composite. Example 1: Is the number 2 prime or composite? Solution: The factors of 2 are 1 x 2.
Example 2: Is the number 9 prime or composite? Solution: The factors of 9 are 1 x 9, 3 x 3. Example 3: Find all prime numbers between 2 and 9. Example 4: Find all prime numbers between 10 and The number 1 is not a prime, since it has only one divisor. The number 4 is not prime, since it has three divisors 1 , 2 , and 4 , and 6 is not prime, since it has four divisors 1 , 2 , 3 , and 6.
Definition: A composite number is a whole number with more than two integral divisors. So all whole numbers except 0 and 1 are either prime or composite. Any number greater than 2 which is a multiple of 2 is not a prime, since it has at least three divisors: 1 , 2 , and itself.
This means 2 is the only even prime. Any number greater than 3 which is a multiple of 3 is not a prime, since it has 1 , 3 and itself as divisors. Any number which is a multiple of 4 is also a multiple of 2 , so we can rule these out. Any number greater than 5 which is a multiple of 5 is not a prime.
There are many puzzles in mathematics that can be solved more easily when we "break up" the Composite Numbers into their Prime Number factors. And a lot of internet security is based on mathematics using prime numbers in a subject called cryptography.
Example: 5 is a prime number. We cannot multiply other whole numbers like 2, 3 or 4 together to make 5.
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