“The probable is what usually happens.”    Aristotle


The probability of an event is a measure of the likelihood that the event will occur.
The probability of any event can range from 0 to 1.

Probability of an event


Predict & Display Data

Probability – Sample Space


Probability Help  

Probability 2 Help



PR09      Counting

PR10      Probability with a Single Die

PR11      Rolling a single die

PR12      Picking numbers out of a hat

PR13      Probability of picking a marble from a bag_1

PR14      Probability of picking a marble from a bag_2

PR15      On the spinner, what is the probability of …

PR16      Probability With a 10-section spinner

PR17      Probability of picking a tile from a bag.

PR18  A Pair of Dice (Probability)


Finding the Probability of Independent Events

(Sample space UNCHANGED)

If A and B are independent events, then

P(A and B) = P(A)•P(B)







Dependent Events (Help),  

Tree Diagram (Help)





Probability Voc

Probability Voc2 



Finding the Probability of Dependent Events  

 (Sample space DECREASES)

If A and B are dependent events, then

P(A and B) = P(A) • P(B given A)


PR19      2Dice

PR21      2Marbles

PR22      2Roses

PR23      2Tiles

PR25      2Bills

PR26  School Items (Probability)

PR27  Marbles (Probability)


Probability – Counting Principle Probability – Independent Event Probability Application

Theoretical probability

Theoretical Probability is determined through reasoning (the ratio of the number of favorable outcomes to the number of possible outcomes).





Experimental probability

Experimental probability is found by repeating an experiment and observing the outcomes.





A monkey is sitting by and hitting 4 keys randomly. Suppose that the monkey is answering a multiple choice MATH STAAR TEST. There are 56 questions and each question has 4 options. Find the experimental probability

PR20      Coin&Die

PR24      3Coins

Probability Writing

Probability_W   Probability Writing

Probability rules