I am leaving this week a bit frustrated. I find probabilities to be rather confusing. It leads me to ask one question. Do elementary students really do these problems? I am thinking it must be geared more towards middle school. Then again maybe I am just trying to make myself feel better for not getting it.
Now, don't get my wrong. I get the importance of probabilities. I think they are an everyday tool, I just think in my head there must be an easier way. I think this is part of my problem though. There isn't a formula you "always" use. It is based on the question. Does it or doesn't it? Regardless, I need more practice and probably should have put in some extra time to try to gain a better understanding of it. And for the students that get this: KUDOS to you!
Since I do like formulas, I am going to focus on one. The definition of odds.
Odds in favor: A = P(A)
Odds against: A = 1- P(A)
These formulas are easy to use and if only they applied to most probability questions, we would be in business.
I found this video on youtube that is called the Monty Hall Problem and discusses the probability of opening a door to win a car and what your strategy should be. It gives the mathematical reasoning behind the choice. It's interesting.