A comprehensive, step-by-step guide covering every concept, rule, and technique you need to master probability at Grade
10 level. From fundamental definitions to worked examples and a full practice examination — everything is here to help
you prepare with confidence.
Core Concepts Set Theory & Rules Visual Tools
Practice Exam Full Memorandum
© E-Loné Scheepers 2026
, CHAPTER 1
Fundamental Concepts &
Terminology
Probability is the branch of mathematics that measures how likely an
event is to occur. Every probability value lives on a scale from 0
(impossible — the event can never happen) to 1 (certain — the event always
happens). A probability of 0.5 means the event has an even chance of
occurring or not occurring. Understanding this scale is your starting point
for everything else in probability.
© E-Loné Scheepers 2026
, CHAPTER 1
The Probability Scale
Use this scale as a mental anchor whenever you calculate a probability. If your answer comes out less than 0 or greater
than 1, you have made an error and should recheck your working. Decimals, fractions, and percentages are all acceptable
ways to express a probability — just be consistent within a question.
© E-Loné Scheepers 2026
, CHAPTER 1
Core Terminology
Before tackling any probability problem, make sure you know these six key terms precisely. Mixing them up is one of the
most common sources of mistakes in examinations.
Experiment
A planned process involving uncertainty that produces observable data. Examples: tossing two coins, rolling a
die, drawing a card from a deck.
Trial
A single execution of the experiment. If you roll a die five times, each individual roll is one trial.
Outcome
One individual result obtained from a single trial. Rolling a 4 on a die is a single outcome.
Sample Space S
The complete set of all possible outcomes. The total count of outcomes is written n(S). For a standard die, S =
{1, 2, 3, 4, 5, 6} and n(S) = 6.
Event E
Any subset of the sample space. The count of outcomes that favour event E is written n(E). "Rolling an even
number" is an event with n(E) = 3.
Empty Set ∅
∅
An event containing zero outcomes — an impossible event. P( ) = 0. Example: rolling a 7 on a standard die.
© E-Loné Scheepers 2026