Work through the levels in order. Type your answer and press Check — open the worked solution if you get stuck. Answers like -6, 3/4 or 0.25 are typed exactly as shown. A ⭐ Bonus Challenge at the end is extra credit — skip it if the rest was hard work.
Level 1 · Warm-up
1 You roll an ordinary dice. Is rolling a 7 possible or impossible?
Show worked solution
A dice only goes up to 6, so rolling a 7 is impossible.
2 A bag holds only red marbles. Pulling out a red one is what?
Show worked solution
Every marble is red, so it is certain.
3 True or false: something unlikely can still happen.
Show worked solution
True — unlikely means it probably will not happen, not that it cannot.
Level 2 · Core
4 A bag holds 4 red and 4 blue marbles. What is the chance of pulling out a red one?
Show worked solution
With equal numbers of each, it is an even chance.
5 A spinner must make red CERTAIN. How much of the spinner has to be red?
Show worked solution
Every part must be red — all of it.
6 A bag holds 9 blue marbles and 1 red. Which colour are you more likely to pull out?
Show worked solution
There are far more blue, so blue is more likely.
Level 3 · Challenge
7 A bag holds 3 red, 1 blue and 6 green marbles. What is the SMALLEST number of red marbles you could add to make red the most likely colour?
Show worked solution
Adding 3 reds gives 6 red against 6 green — equal, not most likely. Adding 4 gives 7 red against 6 green.
8 A spinner is half red, a quarter blue and a quarter yellow. Which is more likely: red, or "blue or yellow"?
Show worked solution
Blue and yellow together make a quarter + a quarter = a half, the same as red. They are equal.
9 A bag holds 5 green and 5 yellow marbles. You take out 3 greens and keep them. Which colour is now more likely?
Show worked solution
The bag now holds 2 green and 5 yellow, so yellow is more likely.
⭐ Bonus Challenge · only if the rest felt easy
10 A bag holds 3 red, 1 blue and 6 green marbles. What is the SMALLEST number of red marbles you could add to make red the most likely colour?
Show worked solution
Green has 6. Adding 3 reds makes 6 red and 6 green — equally likely, not most likely. Adding 4 makes 7 red against 6 green, so red is now the most likely.