What are ...
PRIME NUMBERS?
In today's math class, I mentioned prime numbers. What are they? How do we know which number is a prime number? To understand the concept more clearly, and be able to tell which number is prime of not, read below and follow the links to work on this activity.
Prime numbers are numbers that are greater than 1 and cannot be divided by any number except themselves and number 1. The Greek Eratosthenes created a way to find prime numbers. This method is called the Sieve of Eratosthenes. It is called a "sieve" because you are taking all of the numbers and you are running them through a sieve to separate all of the prime numbers. Here is on online activity for prime numbers, where you have detailed step by step procedures. We can try this together.
Let's Try it....
here's how!
Use this number chart (one that you received in class) to find the prime numbers between 1 and 100.
- Cross out 1, only because all prime number are greater than 1.
- Circle 2, since it is a prime number, but cross out all the multiples of 2 (every second number).
- Circle 3, because it is a prime number as well. Now, cross out all the multiples of 3 (every third number).
- Circle 5, since it is a prime number, and cross out all the multiples of 5.
- Now circle 7, as it is a prime number and cross out all of it's multiples (every seventh number).
- All of the numbers that are circled are the prime numbers from 1 to 100!
