This game reinforces number line concepts and the addition of positive and negative integers.
integers, positive, negative, number line
In this lesson, students play in pairs or groups of three. Each student uses a homemade number line (numbered from -20 to +20, with negative numbers written in red and positive numbers written in black), a colored clothespin, and a set of 2 or 4 dice. Students roll the dice to determine where on the number line they place their clothespins. The first student who passes the number 20 on the number line is the winner.
Before the Lesson
Have each student create a paper number line ranging from negative 20 to positive 20. Students should write negative numbers in red, and positive numbers in black. Zero can be a different color. Then arrange students into pairs or groups of three. Have students in each group decide which color dice will represent positive numbers and which will represent negative numbers. Students in each group then roll a die to determine who goes first.
The student who goes first rolls his or her dice -- two to four dice equally divided between two different colors -- and adds the result. If the student rolls two dice (one white die and one red die, for example), he or she takes the value of the positive die and subtracts the value of the negative die. For example, if the white die is +6 and the red die is -4, the total is (6 - 4 = 2), and the student moves the clothespin to the +2 on his or her number line. If the white die is +2 and the red die is -5, the student figures the total (2 - 5 = -3) and moves the clothespin to the -3 on the number line. (If students are using four dice, they add the value of the two positive dice and then subtract the total of the two negative dice. For example, if the white dice are a +4 and +2, and the green dice are a -2 and -3, the total is ([4 + 2] - [2 + 3] = 1) and the student moves the clothespin to the +1 on the number line. If the white dice are +2 and +4 and the green dice are -5 and -6, the total is ([2 + 4] - [5 + 6] = -5) and the student moves the clothespin to the -5 on the number line.
After the first student's turn is complete, the next student rolls his or her dice. Students take turns rolling the dice and moving their clothespins until one student passes the +20 on the number line. The first student to move his or her clothespin off the number line (on the positive side) is the winner.
The teacher observes the students' play, "coaching," support, and answering questions as desired. At the end of the lesson, ask students provide input about how the game progressed. Ask students for further input about alternative ways to play the game.
Sr. Ann Claire Rhoads, Mother Seton Academy in Baltimore, Maryland
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