## Divisibility Buzz

### Cindy BeckhamSanta Rosa District Schools

#### Description

Students use the divisibility rule for three to compete in the game Divisibility Buzz. This lesson provides enjoyable reinforcement.

#### Objectives

The student uses divisibility rules.

#### Materials

-Clock or watch with a second hand

#### Preparations

1. Teach the divisibility rule for 3 – A number is divisible by 3 if the sum of the digits is divisible by 3.
2. Obtain a watch or clock that has a second hand.

#### Procedures

1. Play this game after the divisibility rule for three has been taught.
2. Before beginning the game, explain the rules to the students. Tell the students that they will stand and begin taking turns counting from 1. If the student’s number is divisible by 3 or has a 3 in it, they must say “buzz.” If the number is not divisible by 3 or does not have a 3 in it, then the student must say the correct number. The response should be made within 20 seconds. Students must listen carefully to keep up with the numbers being spoken. If a student gives an incorrect response, he or she is out of the game and must sit down in his or her seat. The next student must give the next correct response. When the elimination is down to two students, and one of the students makes an incorrect response, the other student must make the next correct response to win the game. Students may not use paper and pencil.
3. The first 50 responses are: “one,” “two,” “buzz,” “four,” “five,” “buzz,” “seven,” “eight,” “buzz,” “ten,” “eleven,” “buzz,” “buzz,” “fourteen,” “buzz,” “sixteen,” “seventeen,” “buzz,” “nineteen,” “twenty,” “buzz,” “twenty-two,” “buzz,” “buzz,” “twenty-five,” “twenty-six,” “buzz,” “twenty-eight,” “twenty-nine,” “buzz,” “buzz,” “buzz,” “buzz,” “buzz,” “buzz,” “buzz,” “buzz,” “buzz,” “buzz,” “forty,” “forty-one,” “buzz,” “buzz,” “forty-four,” “buzz,” “forty-six,” “forty-seven,” “buzz,” “forty-nine,” “fifty.”
4. NOTE: To say “buzz” for numbers having a 3 in them is to make the game more challenging. Stress to the students that just because a number has a 3 in it does not make it divisible by three.

#### Assessments

After the students have had sufficient classroom review (including playing Divisibility Buzz), the students complete a 20 item quiz on divisibility by 3 as a formative assessment. (See associated file.)

#### Extensions

This activity may be used for other rules of divisibility.