Teaching Algebra with Manipulatives

Using Overhead Manipulatives
(Use with Algebra 1, Lesson 2-6)
Experimental Probability
Objective Perform an experiment in order to determine the probability of a
simple event.
Materials
• transparency pens*
• two spinners*
* available in Overhead Manipulative Resources
Demonstration
Experimental Probability
• Explain to students that rolling two dice can be
simulated by spinning two spinners, each divided
into 6 equal parts.
1
6 2
5 3
4
6
1
5
2
3
4
• Spin both spinners twelve times. Tally each time doubles occur.
number of times doubles occur
Ask students to compute the ratio .
12
• Ask students what they think will happen if the number of spins is
increased. The probability of doubles will approach 1 6 .
• Complete as many more spins as you wish, keeping track of the number
of spins and the number of doubles. Have students compute the ratio
number of times doubles occur
.
number of spins
• Ask students to analyze the results of this experiment.
© Glencoe/McGraw-Hill 48 Teaching Algebra with Manipulatives