probability · Year 5 · Suggested learning sequence
Equally likely outcomes
When every outcome is equally likely, the probability of an event is the number of outcomes you want over the total number of outcomes. A spinner with 8 equal sections, 3 of them red, gives P(red) = 3/8. Count sections or counters, not colours. For numbered cards, list the numbers that fit: 'greater than 6' does not include 6. Fractions can be simplified: 4/10 = 2/5.
Sample questions
The spinner has 8 equal sections. What is the probability that it lands on red?
- There are 8 equal sections, so there are 8 equally likely outcomes.
- 7 of the sections are red.
- P(red) = 7/8.
Answer: 7/8
The spinner has 5 equal sections. What is the probability that it lands on green?
- There are 5 equal sections, so there are 5 equally likely outcomes.
- 2 of the sections are green.
- P(green) = 2/5.
Answer: 2/5
The spinner has 10 equal sections. What is the probability that it lands on yellow?
- There are 10 equal sections, so there are 10 equally likely outcomes.
- 1 of the sections is yellow.
- P(yellow) = 1/10.
Answer: 1/10