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 A coin has landed heads three times in a row. What is the chance the next toss is heads?
Show worked solution
Still 1 out of 2.
2 A bag holds 3 red and 5 blue counters. Write the total number of counters, and the number of red ones left after one red is taken and kept.
Show worked solution
8 counters, and 2 red left.
3 The chances of all the outcomes of an experiment must add to what number?
Show worked solution
1.
Level 2 · Core
4 A spinner has 4 equal sections and has landed on red four times running. Which statement is correct?
Show worked solution
Red is still 1 out of 4. A spinner has no memory.
5 Four chances add to 1. Red is 0.2, blue is 0.2, and green and yellow share the rest with green twice yellow. Write the amount green and yellow share, and the chance of yellow.
Show worked solution
They share 0.6, in three parts of 0.2, so yellow is 0.2.
6 A bag holds 3 red of 8 counters. One red is taken and kept. How many counters are left in the bag?
Show worked solution
7.
Level 3 · Challenge
7 A bag holds 4 red, 3 blue and 3 green counters.1 Red is the most likely colour.
2 Red is likely.
3 Blue and green are equally likely.
Which statements are correct?
2 Red is likely.
3 Blue and green are equally likely.
Which statements are correct?
Show worked solution
4 beats 3 and 3 (1 ✓), but 4 of 10 is under a half, so red is not likely (2 ✗). Blue and green are both 3 of 10 (3 ✓). 1 and 3.
8 A bag holds 3 red and 5 blue. A red is taken and kept, then a blue is taken and kept. Write how many counters remain and how many of them are red.
Show worked solution
6 counters, of which 2 are red.
9 Four outcomes have chances adding to 1. Three of them are 0.15, 0.25 and 0.3. What is the fourth, as a decimal?
Show worked solution
0.15 + 0.25 + 0.3 = 0.7, so the fourth is 0.3.