Probability — NSW Year 7 Maths
The maths of chance, from tossing coins and rolling dice to reading a weather forecast. Five subtopics and 100 practice questions, each with a fully worked solution, aligned to NESA outcome MA4-PRO-C-01.
Probability in NSW Year 7
Probability is a number from 0 to 1 that describes how likely something is to happen. In Year 7, students list the possible outcomes of simple experiments with coins, dice, spinners and bags of marbles, calculate probabilities when the outcomes are equally likely, describe chance in words, collect results from repeated trials, and use the fact that any event and its complement add to 1.
The five subtopics below start with sample spaces, then calculate probabilities as fractions, decimals and percentages, place them on a scale from impossible to certain, compare theory with experimental results, and finish with complementary events. Probability is one of the 13 topics in NSW Year 7 Maths and sits in the Statistics and Probability strand (NESA outcome MA4‑PRO‑C‑01). In Stage 5 it extends to experiments with two or more steps, Venn diagrams and two-way tables.
Subtopics
Probability: common questions
What is probability in Year 7 maths?
Probability measures how likely an event is, on a scale where 0 means impossible and 1 means certain. Year 7 students find probabilities for simple experiments with equally likely outcomes, such as rolling a die or picking a marble from a bag.
How do you calculate a probability?
Divide the number of favourable outcomes by the total count of equally likely outcomes. A bag with 5 red and 3 blue marbles gives \(P(\text{red}) = \frac{5}{8}\).
What is the difference between experimental and theoretical probability?
Theoretical probability is what you expect under fair conditions, such as \(\frac{1}{2}\) for heads. Experimental probability comes from real trials, as a relative frequency: 120 heads in 200 tosses gives \(\frac{120}{200} = 0.6\). With more trials the two usually get closer.
Which NESA outcome covers probability?
Probability sits in Stage 4 of the NSW Mathematics K–10 Syllabus (2022) under outcome MA4‑PRO‑C‑01, usually taught in Year 7.
What is a complementary event?
An event’s complement is every outcome that is not in the event, and the two probabilities add to 1. If the chance of rain is \(0.08\), the chance of no rain is \(1 - 0.08 = 0.92\).