Show your students a quarter. Explain that you will flip the coin. Ask the students to indicate through a show of hands whether they think the coin will land on heads or tails. Flip the coin and announce the results. Ask your class, "What was your probability of successfully guessing the correct side of the coin?"
Explain the concept of probability to your students and write the definition on the board. Point out the definition in the students' textbooks. Put the definition into your own words, as well. You can tell your students that probability is the use of mathematical calculations to determine the likelihood of an event.
Work through a probability problem together on the board. For instance, if you toss a coin once, and you are guessing that it will land on tails, you have a 50 percent chance of guessing correctly. Set up the problem as a fraction. Write the number of events that you are predicting (which is 1 in this example) in the numerator and the total number of possible outcomes (which is 2 in this problem) in the denominator. Explain that 1 divided by 2 is 0.5, or 50 percent.
Assign additional problems for your students to practice. These problems can come from the textbook, or you can design your own. Depending on the specific needs of your students, you can assign individual or group work. Once the students have completed their work, review the answers together to make sure that everyone understands the concept.
Pair your students and give each pair a spinner that has four colors. Tell your students to choose one color each. Discuss how a student has a 1 in 4 chance of having the spinner land on his or her color with each spin, which translates to a 25 percent chance. Expand this concept by explaining that each pair will spin the spinner 50 times and record the results. Ask the pair to make a prediction as to how many times the spinner will land on a chosen color. In this situation, the students would set up a problem as follows: 1/4 (likelihood that the spinner will land on a certain color in one spin) x 50 (number of spins). When you divide 50 by 4, you get 12.5. Therefore it is likely that the spinner will land on each student's color 12.5 times out of 50. Once the game is finished, compare the actual results with the prediction the students made at its start.