# Probability Using Tactile Spinner

By Tara Mason on Apr 24, 2017

Student will learn about probability of an event occuring using multiple materials. This lesson will also reinforce probability math concepts for students using tactile or high contrast media.

• Understanding probability close to 1 means very likely
• Able to determine probability of a chance event and use probability to predict relative frequency

## Materials

• Braille or high contrast spinner
• Bag with three kinds of textured objects
• Three quarters

## Procedure

This lesson will help reinforce probability concepts. If your student is working in a general education classroom, 7th grade is the first time probability is coming up in the CCSS and this lesson will provide an opportunity for your student to practice using math materials specific to his/her learning needs. Teachers should have an example spinner created, either high contrast or braille spinner, showing unequal parts.

### Steps:

1. What is the probability that the spinner will land on the green section?
2. We will be calculating the probability of an event by creating a ratio. Students can use scratch paper with the spinner to hypothesize the ratio of each probability.
3. Do some example ratios with shapes or objects that students can do independently. For example, set out five textured shapes or high contrast shapes, have student identify the ratio of shapes depending on what is asked, i.e., what is the ratio of purple stars to total stars? Or what is the ratio of squares in this group of circles and squares. Students will need to count the total number and then put the group number in the numerator.
4. Remind students, a common mistake when setting up probabilities is that every event must have an equal probability of occurring. Take a look at the spinner you have provided. Are there equal sections?
5. The definition of probability is: the likelihood that a certain event will take place. Brainstorm times where someone uses probability in their everyday life? An example might be when we check the weather report and weigh the chances of rain. Give some examples of rain probability to find out whether your student would bring an umbrella or raincoat?
• A probability equation is set up: P(A)= which means probability of "A" over the total possible outcomes.
6. Using the example spinner divide it into equal parts with your student, then set up the equation of parts having a consistent total number. Do some example problems together.
• Have your student figure out the ratios for the different categories presented by your spinner.
7. Extension activities, once your student has completed the spinner ratios, have him/her do some extension activities. The first problem can be done together. Using your bag of textured objects, ask your student a word problem connected to your objects. For example, If John has a bag of objects-- 3 circles, 5 squares, 2 triangles and 4 hexagons, what is the probability he will choose a square or a triangle?
• Go through the problem together. Steps: add up all the objects, set up the probability ratio by adding triangles and squares, then create the ratio- 7/14= 1/2. Try out the activity by shaking the bag and letting one spill out per trial.
8. Other possible extension activities: using a tactile number cube to create probability ratios for rolling a particular number or flipping a coin. Try each activity with your student recording the results of 25 or more rolls or flips. Compare the experiment ratios to the probability ratio.