Prime Time

Designed by: Cindy Page    School: Burton-Pack Elementary

Grade Level: 5     Subject(s): Math

Core Curriculum Objective(s): Demonstrate and use the concepts of multiple, factor, and divisibility to identify prime or composite numbers. (5NR4-3)

Overview: Students will use a hundreds board to determine the numbers between 1 and 100 which are prime. They will develop a card game which will require them to use their knowledge of prime and composite numbers. The card games will be played in class and will be scored by their classmates.

Focus/Essential Question(s): What are prime numbers? What are composite numbers?

Time Frame: Three one-hour classes

Resources/Materials: 
* hundreds board for each student 
* overhead transparency of a hundreds board 
* overhead pens 
* index cards 
* several decks of playing cards 
* overhead projector 
* pencil 
* paper * computer 
* Markers or crayons 
* Chalkboard/dry erase board 
* Chalk/dry erase markers

 www.mathgoodies.com/lessons/vol3/prime_composite.html/

Optional:
www.utm.edu/research/primes/ 

www.primepuzzles.net

Culminating Assessment: Students will create a card game which will be played in the classroom by their classmates. The game will require each player to demonstrate his/her knowledge of prime and composite numbers. The games will be played by students in the class and they will score each game. The class will determine the characteristics of a good game and will develop a rubric to score each game. A sample rubric may look something like the following:

 Instructional Activities: 

ACTIVITY ONE: (Students should have previous knowledge of factors and multiples.) Distribute a hundreds board to each student and display one on the overhead projector. Review the terms factor and multiple. Call on a student to call out several multiples of 2. As the numbers are called out, mark an X over them on the hundreds board. Instruct students to place an X over the multiples of 2 on their individual boards.

Repeat the process by marking out all the multiples of numbers 3-10. The following marks can be made for the multiples of each number: * Multiples of 2- make an X * Multiples of 3- draw a 0 * Multiples of 4- draw a * * Multiples of 5- draw a + * Multiples of 6- draw a = * Multiples of 7- draw a / * Multiples of 8- draw a \ * Multiples of 9- draw a > * Multiples of 10- draw a < (The above list is only a suggestion. Many different symbols can be used, as well as colored markers.) Note: During this process, it is important to not mark out the 2, 3, 5, or 7 since they are prime numbers less then 10.

When all multiples have been marked, call on a student to read out the numbers which are not marked. Inform students that these numbers are called prime numbers. The teacher should then tell students that prime numbers have exactly two factors, one and the number itself. Call on students to supply numbers larger than 100 which are prime.

The teacher must then inform students that the numbers which are crossed out are called composite numbers. Tell students that composite numbers have three or more multiples. Call on students to supply numbers larger than 100 which are composite.

At this time, it is necessary to tell students that there is one number on the hundreds board which is neither prime or composite. Based on the discussed definitions, ask students to point to the number that is neither prime or composite. Circulate around the room to observe what number each student has selected and call on a student who correctly selected the number 1. Remind students that prime numbers have two factors, but the number 1 has only one factor.

HOMEWORK: List 5 prime numbers greater than 100 and 5 composite numbers greater than 100.

ACTIVITY TWO: 
Review the terms prime and composite. Draw a T-chart on the overhead and label one side PRIME and the other side COMPOSITE. Call on a student to read a number he/she wrote for homework and then ask another classmate to indicate where the number should be placed in the T-chart. The student should be able to give an explanation as to why the number is prime or composite. The student who determined the placement of the number should then call out a number that he/she wrote for homework and call on a classmate to tell whether it is prime or composite. Repeat this process until each student has participated.

Show the students the website http://www.mathgoodies.com/lessons/vol3/prime_composite.html/ and work through the activities. This is an interactive website, with activities and examples to complete. Another good website is called "The Prime Page" and can be found at http://www.utm.edu/research/primes/. This site does not contain activities or questions to answer, but is a good source for prime numbers. (Some of the information will be too advanced for fifth graders, so the teacher should preview the site to see find out what information to use.) Finally, another possible website to use is found at http://primepuzzles.net . (This site has puzzles dedicated to prime numbers which can be used as homework assignments, but again many of the puzzles are too difficult for fifth grade students. The teacher should also preview this site if it is to be used.)

Discuss with the students some card games they like to play. Discuss what makes a card game fun and write their ideas on the board. Tell them that they will be separating into groups and creating a card game for their classmates to play. Remind students of their list of things which make a card game fun.

Tell students that each card game will be scored by their classmates and that they need to determine how those scores will be determined. Display a sample rubric used in a previous activity to show students that the class will need to set up the points and the criteria for the games. Lead the class in a discussion as to how to evaluate the games, starting with a score of 0. The class should determine how many points the rubric should contain, but 3, 4, or 5 points are used most frequently.

Once the rubric has been completed by the class, separate the students into groups of 3 or 4. Groups are to develop a card game which will require players to use their knowledge of prime and composite numbers to complete the game. (Note: Games do not need to be 100% original, they can be variations of well-known card games.) Groups will have the option of using a standard deck of cards or creating numbered cards of their own, using index cards. The created game should have a written set of directions so that the game can be played by anyone.

ACTIVITY THREE: 
Allow groups to continue working on their games. The teacher will need to circulate around the room, offering assistance as needed. When groups finish, they will need to play their new game in order to make sure that the directions are clear.

Once all games have been created, tell students that they will be passing their cards and the directions to another group. The teacher will call on one person in each group to pass the materials to another group. Groups will attempt to play the game as written in the directions. after fifteen to twenty minutes, remind the students that they will be scoring the game. Each student will need a piece of paper and should write down the name of the game, a score, and a justification (reason) for that score. As each game is played, allow students to record the name, the score, and a justification.

Repeat the process of exchanging games. As each game is played, allow students to record the name, the score, and a justification. Collect the score sheets. Note: The teacher will need to determine how to come up with a final score for each game, perhaps by averaging the students' scores.