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 What is the complement of "the coin lands on heads"?
Show worked solution
The coin lands on tails.
2 P(A) = 1/4. Find P(not A). (as a fraction)
Show worked solution
1 − 1/4 = 4/4 − 1/4 = 3/4.
3 P(winning) = 0.3. Find P(not winning). (as a decimal)
Show worked solution
1 − 0.3 = 0.7.
Level 2 · Core
4 P(rolling a 6) = 1/6. Find P(not rolling a 6).
Show worked solution
6/6 − 1/6 = 5/6.
5 The chance of being late is 35%. Find the chance of NOT being late. (like 20%)
Show worked solution
100% − 35% = 65%.
6 P(red) = 3/8. Find P(not red). (as a fraction)
Show worked solution
8/8 − 3/8 = 5/8.
Level 3 · Challenge
7 P(not blue) = 7/10. Find P(blue). Simplify if you can. (as a fraction)
Show worked solution
10/10 − 7/10 = 3/10. Check: 3/10 + 7/10 = 1.
8 A bag has 2 red, 3 blue, 4 green and 1 yellow counter. Use the complement to find P(not red). Simplify. (as a fraction)
Show worked solution
P(red) = 2/10 = 1/5, so P(not red) = 1 − 1/5 = 4/5.
9 A bag has 2 red, 3 blue, 4 green and 1 yellow counter. Find P(not green). Simplify. (as a fraction)
Show worked solution
P(green) = 4/10 = 2/5, so P(not green) = 1 − 2/5 = 3/5.