The Probability Scale
Probability tells us how likely an event is to happen. We write probability as a number from 0 to 1.
Place each of the following events on the probability scale below by writing the letter in the correct position.
- Flipping tails on a fair coin
- Rolling a number less than 7 on a standard die
- Picking a blue marble from a bag of 10 red marbles
- Drawing an even number from cards numbered 1–10
- It will rain somewhere in the world today
- Spinning a spinner with 3 equal sections and landing on section 1
Probability Scale
Probability Quick Questions Grid
Answer each question below. Write your probability as a fraction, decimal, or percentage — or all three! Use the scale from Section 1 to help you.
Q1. A bag has 5 red and 5 blue marbles. What is the probability of picking a red marble?
P(red) =
Where does this sit on the 0–1 scale?
Q2. A fair die is rolled. What is the probability of rolling a 6?
P(6) =
Is this likely or unlikely?
Q3. A spinner has 4 equal sections coloured red, blue, green, and yellow. What is the probability of landing on green?
P(green) =
Write this as a decimal:
Q4. A jar has 3 lollies: 1 strawberry, 1 cola, 1 mango. You pick one without looking. What is the probability of getting strawberry?
P(strawberry) =
Write as a percentage:
Q5. A bag has 8 green counters and 2 yellow counters. What is the probability of picking a yellow?
P(yellow) =
Is this closer to 0 or 1?
Q6. Cards numbered 1 to 10 are shuffled. What is the probability of picking a card greater than 7?
Favourable outcomes:
P(greater than 7) =
Q7. A coin is flipped. What is the probability of getting heads or tails?
P(heads or tails) =
What type of event is this?
Q8. A box has 6 apples. You pick one fruit. What is the probability of picking an orange?
P(orange) =
What type of event is this?
Q9. A spinner has 3 sections: 2 red, 1 blue. What is the probability of landing on red?
P(red) =
Mark this on the 0–1 scale: closer to
Q10. A bag has 4 purple, 3 orange, and 3 white beads. What is the probability of picking a purple bead?
P(purple) =
Write as a decimal:
Q11. A die is rolled. What is the probability of rolling an even number?
Even numbers on a die:
P(even) =
Q12. A bag has 10 blue marbles only. What is the probability of picking a blue marble?
P(blue) =
What is this type of event called?
Reflect & Create
Think about what you have practised. Use these questions to show your understanding and push your thinking further.
R1. Write your own example of an event with a probability of exactly 0.5. Explain why.
R2. Which question from the grid did you find trickiest? What made it difficult?
R3. Design your own. Create a probability question using a bag of coloured marbles. Write the question, then work out the answer.
My question:
My answer: