🎲 Probability

How likely is it? Learn to describe chance!

📖 Learn
Likelihood language
✏️ Examples
Worked problems
🔬 Visualiser
Interactive spinner
🎯 Practice
20 mixed questions

📖 Probability

1. Likelihood Words

Impossible → Unlikely → Even chance → Likely → Certain

Impossible: Will never happen (e.g. rolling a 7 on a standard dice)

Unlikely: Could happen but not often

Even chance: Equally likely to happen or not (e.g. flipping heads)

Likely: Probably will happen

Certain: Will definitely happen (e.g. rolling a number < 7)

2. Probability Scale 0 to 1

0 (Impossible)
1 (Certain)

Impossible = 0, Even chance = 0.5, Certain = 1

The closer to 1, the more likely!

3. Coins, Dice and Spinners

Coin: 2 outcomes — Heads or Tails. P(heads) = 1/2 = 0.5

Dice (1–6): 6 outcomes. P(any one number) = 1/6

Spinner: Number of equal sections = total outcomes. P(one section) = 1/n

4. Listing Outcomes

List ALL possible results to count total outcomes.

Dice outcomes: {1, 2, 3, 4, 5, 6} → 6 total

P(even) = 3/6 = 1/2

5. Comparing Likelihood

Which is more likely: rolling a 6 or rolling an even number?

P(6) = 1/6  |  P(even) = 3/6 = 1/2

1/2 > 1/6, so rolling even is more likely.

✏️ Worked Examples

Example 1 – Likelihood Words

Describe the chance of picking a red ball from a bag of 5 red and 1 blue.

5 red out of 6 — most are red
= Likely

Example 2 – Probability as a Fraction

A dice is rolled. P(number < 3) = ?

Numbers less than 3: {1, 2} = 2 outcomes
Total outcomes = 6
P = 2/6

Example 3 – Counting Outcomes

A spinner has 4 equal sections. How many equally likely outcomes?

4 equal sections → 4 outcomes

Example 4 – P as a Decimal

A spinner has 4 equal sections. P(landing on one section) = ?

P = 1/4 = 0.25
= 0.25

Example 5 – Comparing

Is P = 3/4 more likely or less likely than P = 1/4?

3/4 = 0.75  |  1/4 = 0.25
0.75 > 0.25 → 3/4 is more likely

🔬 Interactive Spinner

Set Sections



Your Spinner

Exercise 1 – Likelihood Codes

Enter: 0=impossible, 1=unlikely, 2=even chance, 3=likely, 4=certain

Exercise 2 – Probability as a Fraction (dice, denominator 6)

Enter just the numerator for each probability.

Exercise 3 – Number of Equally Likely Outcomes

Count the total equally likely outcomes.

Exercise 4 – Probability as a Decimal

Give probability as a decimal (to 3 decimal places where needed).

Exercise 5 – Compare Likelihood

Enter 1 if first event is more likely, 0 if second is more likely, 2 if same.

🎯 Practice – 20 Questions

🏆 Challenge