Class Notes:
Class Notes Course 1 Chapter 1 Lesson 1 Course 2 Chapter 5 Lesson 1
Class Handouts:
Use this hundreds chart worksheet to solve the Sieve of Eratosthenes Credit: This worksheet was obtained from themathworksheetsite.com
Prime Numbers
How can I tell if a number is prime?
Solve the Sieve of Eratosthenes:
Directions:
1. Use the hundreds worksheet with numbers from 1 to 100.
2. Use a highlighter to color in the number 1. It is NOT a prime number.
3. The number 2 is a prime number. Only 2 x 1 = 2.
Do NOT highlight the number 2.
4. Color in with a highlighter ALL of the multiples of 2. Remember Do NOT highlight 2. Begin with 4, 6, 8, 10, etc. To find these numbers skip count by 2.
5. DO NOT highlight the number 3. 3 is a prime number. ONLY 3 x 1 = 3.
6. Color in with a highlighter ALL of the multiples of 3 or every third number after three. 6, 9, 12, 15, 18, etc.
7. DO NOT highlight the number 5. 5 is a prime number. ONLY 5 x 1 = 5.
8. Color in with a highlighter ALL of the multiples of 5 beginning with the number 10, 15, 20, 25, etc.
9. DO NOT highlight 7.
10. Color in with a highlighter ALL of the multiples of 7 beginning with the number 14, 21, 28, etc.
IF you have highlighted your worksheet correctly, all of the non-highlighted numbers are prime numbers. All of the highlighted numbers are composite numbers.
You can check to see if your worksheet is correct at the end of this blog post.
Prime Numbers, Composite Numbers, Neither Prime nor Composite numbers:
Here is a slideshow presentation that helps explain how to tell if a number is prime or composite.
Prime Factorization
How to find the prime factors of a number (called prime factorization)
TEACHERS: This site has a great bulletin board for prime factorization called Mt. Factor:
Math work stations/bulletin board ideas
http://faculty.kutztown.edu/schaeffe/BulletinBoards/bbs.html
Great upper-level math bulletin board ideas each with purposeful, engaging content; interactivity; and accessibility. Could be used for math work stations as well.
Check this handout to see if you solved the Sieve of Eratosthenes correctly. Prime Numbers 100s chart (numbers 1-100-prime numbers highlighted; composite numbers NOT highlighted) Prime numbers 100s chart .jpg
Factor Tree Game at www.mathgoodies.com
Prime Factorization Calculator at www.mrnussbaum.com
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