Grade 7 Probability worksheet
from Gradelings · Name: ______________________
How to explain it
- Probability = favourable outcomes ÷ all possible outcomes.
- It is always between 0 (impossible) and 1 (certain).
- For two events, list every outcome so none are missed.
Example: You roll a die. What is the probability of an even number? Even numbers: 2, 4, 6. That is 3 outcomes. There are 6 outcomes in all. 3/6 = 1/2. Answer: 1/2
Question 1
The table shows every outcome of flipping a coin (H or T) and rolling a die. How many outcomes show a 5 or a 6 (with either coin side)?
Coin 1 2 3 4 5 6 H H1 H2 H3 H4 H5 H6 T T1 T2 T3 T4 T5 T6 answer box
4
Hint: Find the matching cells: H5, H6, T5, T6. That's 4 of the 12 outcomes.
Question 2
Suppose you flip a coin and roll a standard die (1 to 6), and repeat this 270 times. About how many times would you expect to get heads and a number greater than 4?
answer box
45
Hint: P(heads and a number greater than 4) = 1/2 × 2/6 = 1/6. Expected: 1/6 × 270 = 45 times.
Question 3
You flip a coin and roll a standard die (1 to 6). What is the probability of getting heads and a multiple of 3? Give a fraction.
answer box
1/6
Hint: The events are independent, so multiply: P(heads) × P(a multiple of 3) = 1/2 × 2/6 = 2/12 = 1/6.
Question 4
Two coins were flipped together 50 times. Based on these results, what is the experimental probability of "one head, one tail"? Give a fraction.
50 flips of two coins Result Count Two heads 16 One head, one tail 22 Two tails 12 answer box
11/25
Hint: Experimental probability = times it happened ÷ total trials = 22/50 = 11/25.
Question 5
As you do more and more trials, the experimental probability usually…
- always equals exactly 1/2
- gets farther from the theoretical probability
- stops changing after 10 trials
- gets closer to the theoretical probability
gets closer to the theoretical probability
Hint: Small experiments can be lopsided. With many trials, results tend to settle near the theoretical probability.
Question 6
You roll a standard die (1 to 6) and spin a spinner with 5 equal sections. How many different outcomes are possible?
answer box
30
Hint: Each of the 6 results of the first event can pair with each of the 5 results of the second: 6 × 5 = 30 outcomes. A tree diagram or table shows them all.
Question 7
You spin this spinner (4 equal sections) and flip a coin. What is P(orange and heads)?
- 1/8
- 3/4
- 1/4
- 2/6
1/8
Hint: P(orange) = 1/4 and P(heads) = 1/2. The events are independent, so multiply: 1/4 × 1/2 = 1/8.
Question 8
Two spinners are each half red and half blue. Sam spun both 20 times, and both landed on red 6 times. What is the experimental probability of "both red" as a percent?
answer box%
30 %
Hint: Experimental probability = 6/20 = 0.3 = 30%. Compare it with the theoretical probability: 1/2 × 1/2 = 1/4 = 25%.
Question 9
Two events are independent when…
- they can never both happen
- the result of one doesn't change the chances of the other
- one event causes the other
- they always happen at the same time
the result of one doesn't change the chances of the other
Hint: Flipping a coin doesn't affect a die roll. That's what independent means.
Question 10
Two spinners are each half red and half blue. Zoe spun both 100 times, and both landed on red 20 times. What is the experimental probability of "both red" as a percent?
answer box%
20 %
Hint: Experimental probability = 20/100 = 0.2 = 20%. Compare it with the theoretical probability: 1/2 × 1/2 = 1/4 = 25%.
Answer key
- 1. 4
- 2. 45
- 3. 1/6
- 4. 11/25
- 5. gets closer to the theoretical probability
- 6. 30
- 7. 1/8
- 8. 30 %
- 9. the result of one doesn't change the chances of the other
- 10. 20 %
Want more than 10 questions?
In Gradelings the questions change every time and adjust to your child, with hints and kind feedback.