Probability for Grades 6–8
Eight focused skills: basic probability, events, counting outcomes, expected frequency, compound events, complements, without-replacement probability, and expected value.
Browse the skills
Each card opens a parent-readable explanation. Most also link straight to matching Numeris practice; a few link to the closest practice topic instead.
Basic Probability
Probability measures how likely something is, as a fraction from 0 (impossible) to 1 (certain).
Practice / Learn →Probability of an Event from a Spinner
When an event can happen in several ways, count all the favorable outcomes and divide by the total.
Practice / Learn →Counting Outcomes — the Counting Principle
Before you can find a probability by counting, you need the sample space: every outcome that can happen.
Practice / Learn →Expected Frequency
If you repeat an experiment many times, the expected number of times an event happens is its probability times the number of trials.
Practice / Learn →Probability of Compound Events
Two events are independent if one doesn't affect the other (like two separate coin flips).
Practice / Learn →Complement of an Event
The complement of an event is everything except that event.
Practice / Learn →Probability Without Replacement
Sometimes one draw changes the next — like pulling marbles and not putting them back.
Practice / Learn →Expected Value
Expected value is the average result of a choice over many tries.
Practice / Learn →Jump into the interactive rooms.
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