In mathematics, there are many different kinds of numbers. Some of these types, such as even and odd numbers, are very common and easily understood. Other types of numbers are not quite so easy to identify. But if you can recognize and understand the meaning of all the different types of numbers, you will be more apt to do well in your mathematics courses. One type of number that you need to understand thoroughly is the prime number. It may take a little review and practice, but the tips below should help you determine a prime number.
Instructions
1. Review the definition of factor of a whole number. To determine a prime number, you must be able to identify the factors of a whole number. A whole number is a factor of another whole number if it will divide into the number evenly. That just means there will be no remainder (other than zero) when the number is divided. For example, the number 2 is a factor of the number 6 because when 6 is divided by 2, the answer is 3 with no remainder. The number 4 is not a factor of 6 because it doesn't divide into 6 evenly. All the factors of the number 6 are 1, 2, 3 and 6.
2. Look at another example of factors of a number. All the factors of the number 12 are 1, 2, 3, 4, 6 and 12. Those are the only numbers that will divide into 12 evenly, or with no remainder. An example of a number that is not a factor of 12 is the number 5. When 12 is divided by 5, the answer is 2 with a remainder of 2. Since there is a remainder, that means 5 doesn't divide into 12 evenly so 5 is not a factor of 12.
3. Understand the definition of a prime number. A prime number is a whole number that has exactly two factors, the number 1 and the number itself.
4. Determine if a number is prime by looking at its factors. Use the number 5 as an example. The only factors of 5 are 1 and 5. According to the definition in Step 3, that makes 5 a prime number. Look at another example, the number 6. As stated in step one, the factors of 6 are 1, 2, 3 and 6. Since 6 has more than two factors, 6 is not a prime number.
