Probability and Basic Exercises

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Understanding Basic Probability

6 Sided Dice

Probability

refers to the chance or liklihood of an event happening.


The basic formula for probability is:

Probability = Number of Favorable Outcomes/Number of Possible Outcomes

Take a six sided dice, you want to know what the probability is of rolling a four. There are only six numbers on the dice. Using the formula above, you know that there is a one in six chances of rolling a four. Thus, the probability is 1/6

What about rolling a one? Again, there is only a single one on a six sided dice. Again, the probability is 1/6 or one is six chances of rolling a one.

We can take this further and say what is the probability of rolling a one or a four? Using the formula above, we have 2 favorable outcomes over 6 possible outcomes. We know that there's two in six chances of rolling a one or a four which is 2/6 or 1/3. What does this mean? If you roll the dice 6 times, you are likely to roll a one or a four twice. If you roll the dice three times, you are likely to roll a one or a four once.

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Spinner Probability

Previously, you saw the basics of probability using a six sided dice. This time we have a colored spinner. The spinner has 12 sections in it. Notice that there are five red sections, one yellow section, three green sections and three blue sections.

What is the chance of the spinner landing on yellow? Again using the probability formula:

Probability = Number of Favorable Outcomes/Number of Possible Outcomes

We know that there is only one yellow section out of twelve possible outcomes.
Therefore there is a one in twelve chances of landing on yellow: 1/12 which means, if you spin twelve times, you will likely land on yellow once. However, this is only probable, if you conducted the experiment, you may land on it more often or not at all. Probability is not exact.

Let's look at the probability of landing on red. How many red sections are on the spinner?

There are five red sections on the spinner and 12 sections in total. Therefore, the probability of landing on red is five out of 12 possible chances: 5/12
Which means, if you spin 12 times, the probable outcome of landing on red is about five times.

Again, if we look at either blue or green, we know that there are three sections or favorable outcomes out of 12 possible outcomes. Therefore the probable outcome of landing on green is three out of 12 or 3/12 or 1/4. Hence, if you spin the spinner four times, you have a probability of landing on green once.

The basics of probability if often introduced in the early grades, as early as the second grade and appears in the curriculum throughout your math career.

Let's put our theory to action in basketball! or check out what the odds are of going to jail in one of my favorite games: Monopoly!