Probability for Kids: A Guide for Beginners
In middle school, you'll study probability, which is helpful in many aspects of everyday life. Keep reading to learn about probability models for simple and compound events!
Probability Guide
Probability is the likelihood that an event will occur. It's often expressed as a decimal or fraction between one and zero, where zero means there's no chance the event will occur, and one means the event will definitely occur.
Simple Events
The probability that a single event will occur is equal to one over the total number of possible events. For instance, if you're rolling a 6sided die, the probability that you'll roll a six is 1/6, since there are six possible outcomes. The probability that you'll roll any other number on the die, like a two or a four, is also 1/6.
You can also calculate the probability that one of several events will occur. For example, you might want to calculate the probability that you'll roll either a six or a three. Since you're interested in two events out of six that could possibly occur the probability is 2/6. Likewise, the probability that you'll roll a number less than six is 5/6, since five of the numbers out of the six on the die are lower than six (one through five).
Compound Events
You will also learn to evaluate the probability of multiple events happening simultaneously or over time. For example, you might want to know the probability that it will rain on both Saturday and Sunday. To calculate this, compare the number of events you're interested in to the total number of possible outcomes, just as you did with simple events.
In this example, there are four possible outcomes: rain on Saturday but not Sunday, rain on Sunday but not Saturday, rain on both days and no rain on either day. You're interested in one of them (rain on both days), so the probability is 1/4.
Reporting Probabilities
While probabilities are often reported as fractions, they can also be expressed as ratios, decimals or percentages. For instance, we can say that there's a 1/4 (one in four) chance that it will rain on both Saturday and Sunday, but we can also express that as 1:4. Yet another way to write this probability is 0.25, since 1/4 = 1 ÷ 4 = 0.25. The decimal 0.25 is equal to 25%, so we could also say there's a 25% chance that it will rain on both days.
Other Articles You May Be Interested In

The SOL is Virginia's statewide, standardized educational assessment test required of students in 3rd, 5th, and 8th grades. Read on to understand the methods and rationale behind the test, as well as tips for how to prepare for it.

Are America's children spending too much time in front of TV, computer and smartphone screens? According to a recent study, the answer is yes, more time than ever before. And while some apps and TV shows might be geared toward building skills in young children, some experts suggest that too much screen time is simply not...
We Found 7 Tutors You Might Be Interested In
Huntington Learning
 What Huntington Learning offers:
 Online and incenter tutoring
 One on one tutoring
 Every Huntington tutor is certified and trained extensively on the most effective teaching methods
K12
 What K12 offers:
 Online tutoring
 Has a strong and effective partnership with public and private schools
 AdvancEDaccredited corporation meeting the highest standards of educational management
Kaplan Kids
 What Kaplan Kids offers:
 Online tutoring
 Customized learning plans
 RealTime Progress Reports track your child's progress
Kumon
 What Kumon offers:
 Incenter tutoring
 Individualized programs for your child
 Helps your child develop the skills and study habits needed to improve their academic performance
Sylvan Learning
 What Sylvan Learning offers:
 Online and incenter tutoring
 Sylvan tutors are certified teachers who provide personalized instruction
 Regular assessment and progress reports
Tutor Doctor
 What Tutor Doctor offers:
 InHome tutoring
 One on one attention by the tutor
 Develops personlized programs by working with your child's existing homework
TutorVista
 What TutorVista offers:
 Online tutoring
 Student works oneonone with a professional tutor
 Using the virtual whiteboard workspace to share problems, solutions and explanations